Two Ukrainian fighter jets were shot down in contested airspace near the Russian border Wednesday as tension between the two countries increased a week after a missile struck a passenger jet, killing all 298 people onboard. 
 
 No one could agree on who fired the missiles that hit the fighter jets. Kiev pointed the finger at Russia, while both the Kremlin and pro-Russia separatists said the separatists were responsible. 
 
 Regardless, the fact that the jets were brought down six days after a suspected separatist-fired missile felled Malaysia Airlines Flight 17 stoked fear of a deteriorating military situation. U.S. intelligence agencies believe Russia has supplied the separatists with dozens of additional rocket launchers and military vehicles in the days since the passenger plane was hit. 
 
 The downing of the airliner, which U.S. officials suspect was a mistake, as well as the global outcry that followed, had raised hope that the fighting in eastern Ukraine might cool off. 
 
 But on Wednesday, battles raged in a number of cities in eastern Ukraine’s Luhansk region after several days of fighting in the center of the separatist stronghold of Donetsk. 
 
 Tension also appeared to be ratcheting up between Russia and Western Europe. A spokesman for German Chancellor Angela Merkel said Merkel “thinks rapid decisions are necessary” because of Russia's lack of cooperation in defusing the conflict in Ukraine. 
 
 Kiev’s Su-25 jets were flying fewer than 10 miles from the Russian border over the southeastern Ukrainian towns of Saur Mogila and Dmytrivka on Wednesday when they were shot down, forcing the pilots to eject. Their whereabouts were not immediately known. 
 
 The incident called to mind the days before the Malaysia Airlines attack, when two military transport planes were brought down by separatist missiles. 
 
 What happened Wednesday, however, remained unclear. 
 
 Igor Korotchenko, a Russian military analyst close to the Defense Ministry, told The Times that “the Russian military had nothing to do with the downing of two Sukhoi jets in eastern Ukraine on Wednesday,” adding that he believed the jets “were shot down by local self-defense forces who used portable antiaircraft missiles.” 
 
 Sergei Kavtaradze, an aide to Oleksandr Boroday, one of the self-proclaimed leaders of the so-called Donetsk People’s Republic, told CNN that separatists hit the planes. Separatist forces used shoulder-fired missiles to bring them down, Kavtaradze said. 
 
 But the Ukrainian government was blaming Russia. 
 
 “They were downed not by terrorists,” Andriy Lysenko, spokesman for the National Security and Defense Council, told reporters in Kiev on Wednesday afternoon, using the government's term for the separatists. “‎According to our preliminary information, it was done from across the border.” 
 
 Lysenko cited the fact that the planes were flying‎ at 17,000 feet as partial evidence that the missiles that brought them down couldn't have come from the separatists. 
 
 Asked whether that contradicted the government's belief that separatists had such capability in bringing down Malaysia Airlines Flight 17, which was flying at nearly twice that altitude, Lysenko said, “This is just based on preliminary data.” He did not elaborate, saying only that “an investigation is being arranged.” 
 
 Kavtaradze and Korotchenko’s accounts raised questions too. Each said the planes were downed by shoulder-fired missile, but if the planes were flying at 17,000 feet, they would have been far beyond the reach of the so-called man-portable systems. 
 
 As of Wednesday afternoon, U.S. intelligence agencies said they had not confirmed the Ukrainian government’s claim that the missiles had come from Russia. 
 
 The agencies have confirmed that Russia had sent dozens of additional rocket launchers and military vehicles to separatists within the last week, according to a U.S. intelligence official who was not authorized to speak publicly. 
 
 To assist the separatist forces, the Russian military has taken “mothballed” models of tanks and other equipment out of storage to match equipment used by the Ukrainian military, said the official. Supplying separatists with equipment that matches the Ukrainian government’s armory gives Russia some “plausible deniability” when confronted about arming the groups, the official said. 
 
 In the days after the airliner was shot down, U.S. intelligence satellites also recorded an increase in the number of military vehicles at a Russian base near Rostov-on-Don, a city about 100 miles east of the Ukrainian border, the official said. 
 
 Army Col. Steve Warren, a Pentagon spokesman, told reporters Wednesday that the Russian military continued to maintain as many as 12,000 troops along the Ukrainian border and was still sending equipment into the country. “We know that they [the Russian military] sent, for example, last week a column of over 100 vehicles which included tanks, artillery, multiple-launch rocket systems,” Warren said. 
 
 Russian President Vladimir Putin has denied supplying the separatists with weapons and accused Ukraine of using the downing of the airliner for political ends. 
 
 One day after European Union foreign ministers agreed to impose sanctions on more Russian officials and entities suspected of contributing to the unrest in eastern Ukraine and Crimea, Germany signaled it could soon be taking a firmer stance toward Russia. 
 
 Europe’s largest economy has been less willing than some of its neighbors to criticize Moscow, in part because of strong trade relations between the two countries. But German government spokesman Georg Streiter’s comments to reporters about Merkel on Wednesday suggested that proposals for tougher sanctions could be put into effect quickly after they are presented to European foreign ministers Thursday. 
 
 Merkel has toughened her stance toward Moscow over the last few weeks despite resistance from some in the German business community. 
 
 Also Wednesday, authorities began transporting the bodies of victims of the Malaysia Airlines downing to their families. A total of 40 bodies were loaded onto two planes bound for Amsterdam in a solemn ceremony in the northeastern Ukrainian city of Kharkiv. 
 
 Ukrainian soldiers lined the runway at the airport as the coffins were carried onto the planes, and government officials from several countries offered short speeches. Hans Docter, a representative from the Dutch government, noted solemnly of the victims, “Today, your journey home begins.” 
 
 As the planes landed at Amsterdam’s Eindhoven Airport, a military trumpet sounded in tribute as Prime Minister Mark Rutte and members of the Dutch royal family gathered. Black hearses pulled up on the tarmac to receive the coffins, and a moment of silence was observed. 
 
 steven.zeitchik@latimes.com 
 
 Times staff writers Brian Bennett in Washington, Sergei L. Loiko in Moscow and Henry Chu in London contributed to this report. ||||| Story highlights Observers say Putin is under pressure at home and abroad 
 
 U.S. officials: Russian troops moving closer to Ukrainian border 
 
 Ukrainian security council spokesman says missiles may have been fired from Russia 
 
 The shootdown comes six days after Malaysia Airlines Flight 17 was brought down 
 
 Were the missiles that shot down two Ukrainian military planes on Wednesday fired from the Russian side of the border? 
 
 That's a possibility that U.S. intelligence analysts are investigating, U.S. officials told CNN on Wednesday. Pro-Russian rebels quickly claimed credit for downing the military planes. And Ukrainian officials claimed the missiles that hit them might have been fired from inside Russia. 
 
 One thing is clear: Tensions in volatile eastern Ukraine seem to be ratcheting up, less than a week after a missile brought down Malaysia Airlines Flight 17 there. 
 
 Some of the 12,000-15,000 Russian troops near the eastern Ukraine border have broken up into smaller groups and moved within five miles or less of the border, and some are even positioned right at the border, according to two U.S. officials. 
 
 The movement gives the Russian troops the ability to fire surface-to-air missiles, rockets and artillery from inside Russia at Ukrainian positions without having to acknowledge their own presence, the U.S. officials said. 
 
 At the same time, the Russians are continuing to reinforce and ship additional weapons into Ukraine "while the world's attention is on MH17," one U.S. official told CNN. 
 
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 There is also intelligence indicating some rebels have left Ukraine and gone across the border into hiding inside Russia. But the officials said it's not known if any of those people were associated with the shoot-down of MH17. 
 
 "What we know is that, incredibly, even after the shootdown of the Malaysia Airlines flight, Russia has persisted in a pattern of destabilization against Ukraine. It's continued to send fighters and heavy weapons, tanks and missile launchers across the Ukrainian border," said Geoffrey Pyatt, the U.S. ambassador to Ukraine. 
 
 If it's confirmed that the missiles that brought down the Ukrainian military planes came from the Russian side of the border, Pyatt told CNN, it would be an "outrageous, continued escalation of the crisis by Russia even after the SA-11 (Russian-made missile system) brought down an airplane, leading to the death of nearly 300 innocent people." 
 
 In response to reports that Russia continues to arm rebels in Ukraine, the White House is now looking at expanding sanctions on Moscow. Just last week, President Obama announced the U.S. would impose new sanctions on specific targets in Russia's critical energy, banking, and defense industries. 
 
 But Deputy National Security Adviser Ben Rhodes told reporters gathered at the White House that the United States might go even further. 
 
 "We're continuing to develop our own set of options. The fact is that Russia continues to arm separatists. And so we think there needs to be continuing ratcheting up," Rhodes told reporters. 
 
 Putin under pressure 
 
 It's unclear whether Wednesday's shootdown was the work of pro-Russian rebels inside Ukraine, or Russian forces themselves -- and whether Russian President Vladimir Putin knew about or approved the operation. 
 
 For months, Putin has accused NATO of building its forces in the region to threaten Russia. 
 
 "The scale of the training and preparedness is also increasing," Putin said recently. "It is important to prepare our defenses on schedule." 
 
 As calls mount from the United States and other Western countries for more stringent sanctions against Russia, Putin took a more conciliatory tone in his most recent public statement. 
 
 "There are calls for us to influence the militants," he said earlier this week. "We will do everything in our power." 
 
 Jill Dougherty, a Russia expert and CNN's former Moscow bureau chief, said Putin is facing enormous pressure both from the international community and domestically. Business elites are pushing to avoid more sanctions, and Russian nationalists want the country to be tougher on Ukraine. 
 
 "You can almost see it, his balancing, he does this when he talks," Dougherty said. "He is a judo expert. And he is prepared, he's ready to parry, thrust and protect Russia from what he expects are going to be the threats." 
 
 Ukraine: Pilots ejected after planes were hit 
 
 An air defense system shot down the Ukrainian jets Wednesday after the pilots completed a task in Dmytrivka, a village in Ukraine's Donetsk region near the border with Russia, the Ukrainian military's press office said. 
 
 The jets' pilots ejected from the planes after they were hit, the military said. Information on their condition wasn't immediately available. 
 
 Sergei Kavtaradze, an aide to rebel leader Alexander Borodai, the Prime Minister of the self-declared Donetsk People's Republic, told CNN that the two jets had been shot down by rebel fighters using a shoulder-fired missile system. 
 
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 But Col. Andriy Lysenko, a spokesman for the Ukrainian National Security and Defense Council, said preliminary information suggested the missiles might have been launched from inside Russia. 
 
 The planes were flying at an altitude of 5,200 meters (17,000 feet) when they were hit, he said. 
 
 News of the jets' downing Wednesday comes six days after the deadly crash of the civilian passenger plane Malaysia Airlines Flight 17 in eastern Ukraine. 
 
 Ukrainian officials have previously accused pro-Russian rebels of shooting down several military aircraft. 
 
 In the week leading up to the July 17 crash of MH17, Ukrainian officials said an Antonov An-26 transport plane and a Sukhoi Su-25 fighter jet had been brought down. The Ukrainian military said the missile that struck the Su-25 had been fired from Russian territory. 
 
 The latest reported shootdown highlights the ongoing conflict in eastern Ukraine's Donetsk and Luhansk regions between the rebels and Ukrainian security forces. 
 
 A CNN team on the ground in Donetsk was turned away by rebel fighters at the entrance to the town of Snizhne, near Dmytrivka. The militants said they had orders not to allow people to travel farther because of fighting. 
 
 A jet could be heard passing periodically very high overhead, while on the ground, ambulances rushed past, as did a convoy of rebel fighters in civilian vans and cars. 
 
 Claim and counterclaim 
 
 The first caskets carrying remains of the crash victims arrived in the Netherlands on Wednesday, where they were met by family members, Dutch King Willem-Alexander and Queen Maxima and other dignitaries. About two-thirds of the 298 victims were Dutch. 
 
 As the solemn tribute continued, accusations did not stop. 
 
 Meanwhile, the finger-pointing continues over who was responsible for bringing down Flight MH17, a Boeing 777. 
 
 U.S. officials say pro-Russian rebels were responsible for shooting down that plane, but they say they now believe it's likely the rebels didn't know it was a commercial airliner, U.S. intelligence officials said Tuesday. 
 
 However, Vitaly Nayda, Ukraine's director of informational security, told CNN's Kyung Lah that the person who shot down the flight was "absolutely" a Russian. "A Russian-trained, well-equipped, well-educated officer ... pushed that button deliberately," he said. 
 
 Moscow has denied claims that it pulled the trigger. And Russian Army Lt. Gen. Andrei Kartapolov suggested a Ukrainian jet fighter may have shot the plane down. Ukraine's government rejects that claim.
– Two Ukrainian military fighter jets have been shot down in the east, the country's Defense Ministry is claiming. The Sukhoi-25 fighters were shot down today at 6:30am Eastern (1:30pm local time) over an area called Savur Mogila. Defense Ministry spokesman Oleksiy Dmitrashkovsky says the planes may have been carrying up to two crew members each. The government says the pilots of the planes ejected, though their location and condition are not currently known, reports the Los Angeles Times. CNN notes that the ministry also believes an air defense system shot the planes down. Ukraine is expected to hold a military briefing later today.