Press office of President 
 
 Due to sharp aggravation of the situation in Donetsk region, President of Ukraine Petro Poroshenko cancelled his working visit to the Republic of Turkey. 
 
 "I have made a decision to cancel my working visit to the Republic of Turkey due to sharp aggravation of the situation in Donetsk region, particularly in Amvrosiivka and Starobeshevo, as Russian troops were actually brought into Ukraine," the President noted. 
 
 Petro Poroshenko informs that the NSDC meeting will be convened today to elaborate further plan of actions. 
 
 "The President must stay in Kyiv today," the Head of State emphasized. 
 
 Ukraine will urgently initiate the convocation of the UN Security Council meeting. "The world must provide assessment of sharp aggravation of the situation in Ukraine," the President noted. 
 
 According to him, Ukraine will address its European partners with a request to call an emergency meeting of the Council of the European Union. 
 
 The President noted that he had made a decision to cancel the visit despite seven bilateral meetings planned within the framework of festivities on the occasion of the Turkish President's inauguration. ||||| NOVOAZOVSK, Ukraine (AP) — The strategically positioned southeastern Ukraine town of Novoazovsk appears firmly under the control of Russia-backed separatists as concerns grow about the opening of a new front in the Ukraine conflict. 
 
 Members of the OSCE examine the scene of a shelling in the town of Donetsk, eastern Ukraine, Wednesday, Aug. 27, 2014. The Obama administration accused Russia on Wednesday of orchestrating a new military... (Associated Press) 
 
 Local residents look at a burned car, hit by shelling in the town of Donetsk, eastern Ukraine, Wednesday, Aug. 27, 2014. The Obama administration accused Russia on Wednesday of orchestrating a new military... (Associated Press) 
 
 On Thursday morning, an Associated Press journalist saw rebel checkpoints at the outskirts and was told he could not enter. One of the rebels said there was no fighting in the town. 
 
 Novoazovsk, which lies along the road connecting Russia to the Russia-annexed Crimean peninsula, had come under shelling for three days, with the rebels entering on Wednesday. The southeastern portion of Ukraine along the Azov Sea previously had escaped the fighting engulfing areas to the north. 
 
 In Donetsk, the largest rebel-held city, 11 people were killed by shelling during the night, the city administration said in a statement. ||||| Media playback is unsupported on your device Media caption Pro-Russian rebels enter the strategically-vital port of Novoazovsk on Wednesday 
 
 A pro-Russian rebel leader in eastern Ukraine has said 3-4,000 Russian citizens are fighting in their ranks. 
 
 Alexander Zakharchenko told Russian TV many of the Russians were former servicepeople or current personnel on leave. 
 
 He was speaking as rebels captured the town of Novoazovsk and threatened to take the city of Mariupol, after opening a new front in the south-east. 
 
 Reports say they are advancing on the city, a key port on the Sea of Azov. 
 
 Ukraine says Russian forces have crossed the border and are supporting the rebel attack, but Moscow has repeatedly denied arming or covertly supporting the rebels. 
 
 There are suspicions that Russia wants to divert Ukrainian forces from the besieged cities of Donetsk and Luhansk, further north. 
 
 Government forces have made significant advances against the separatists in recent weeks. 
 
 In other diplomatic developments: 
 
 An "increasing number of Russian troops" are involved in the fighting, the US ambassador to Ukraine, Geoffrey Pyatt, writes on Twitter 
 
 German Chancellor Angela Merkel demands an explanation from Russia's President Vladimir Putin amid the reports of an incursion 
 
 French President Francois Hollande says it would be "intolerable" if Russian troops are in Ukraine, and demands that Russia stop sending aid to the rebels 
 
 The Organisation for Security and Co-operation in Europe (OSCE) is holding a special meeting in Vienna to discuss developments in Ukraine. 
 
 Ukrainian forces 'leaving' 
 
 Mr Zakharchenko, who is prime minister of the self-declared Donetsk People's Republic, said Russian citizens were coming to Ukraine to fight because they felt it was their duty. 
 
 "There have been around 3,000-4,000 of them in our ranks," he said, adding that the rebels' struggle would have been much harder without them. 
 
 But he insisted that any Russians fighting on the rebel side were doing so voluntarily. 
 
 "Many former high-ranking military officers have volunteered to join us. They are fighting with us, considering that to be their duty," he said. 
 
 "There are also many in the current Russian military that prefer to spend their leave among us, brothers who are fighting for their freedom, rather than on a beach." 
 
 Ukraine's security and defence council confirmed reports that Novoazovsk had been captured by the rebels, whom they described as "Russian troops". 
 
 It said it had withdrawn its forces to save their lives, and they were now reinforcing Mariupol's defences. 
 
 Image copyright AP Image caption There has been shelling in the town of Novoazovsk for several days 
 
 Image copyright AP Image caption Ukrainian forces are being deployed to help defend the southern city of Mariupol 
 
 Image copyright AFP Image caption Shelling is continuing in the city of Donetsk hitting buildings including this school 
 
 Image copyright Reuters Image caption Railway lines in eastern Ukraine have been destroyed in the fighting 
 
 A Ukrainian company commander, Vladimir Shilov, told Ukrainian TV that he had heard from sources inside the town that it was blocked by tanks and no-one was allowed to leave. Local officials had already fled to Mariupol, he added. 
 
 A spokesman for the rebels told Interfax news agency that Novoazovsk was under their control and they would soon "liberate" Mariupol. 
 
 Reports on Twitter suggested the rebels were already advancing towards Mariupol, and rebels said they had captured checkpoints to the west of the city. 
 
 The port has until now been peaceful and cut off from rebel positions. 
 
 Rebels have been trying for weeks to break out of an area further north in the Donetsk region where they are almost encircled. 
 
 Analysts say the separatists could also be seeking a land link between Russia and Crimea, which also would give them control over the entire Sea of Azov. 
 
 Russia annexed the Black Sea peninsula of Crimea from Ukraine in March. 
 
 War in eastern Ukraine: The human cost 
 
 At least 2,119 people had been killed and 5,043 wounded since mid-April, a UN report on 7 August said 
 
 951 civilians have been killed in Donetsk region alone, the official regional authorities said on 20 August 
 
 Official casualty counts only record certified deaths while in some particularly dangerous parts of the war zone, such as Luhansk region, victims are said to have been buried informally, for instance in gardens 
 
 Rebels (and some military sources) accuse the government of concealing the true numbers of soldiers killed 
 
 155,800 people have fled elsewhere in Ukraine while at least 188,000 have gone to Russia 
 
 Ukrainian President Petro Poroshenko promised a roadmap for peace in the east on Tuesday after holding his first direct talks on the crisis since June with Mr Putin. 
 
 Mr Putin said Russia would assist any ceasefire talks, but that stopping the fighting was a matter for Ukraine alone. 
 
 Are you in south-east Ukraine? Have you been affected by recent events in the area? You can send us your experiences by emailing haveyoursay@bbc.co.uk.
– Ukraine's Ministry of Foreign Affairs tweeted a pair of hashtags last night—#UkraineUnderAttack and #RussiaInvadedUkraine—which appear to sum up the situation on the ground, the Washington Post reports. Pro-Russia separatists backed by Russian troops, artillery, and armored vehicles are now attacking on two fronts, authorities in Kiev say, with fierce fighting along a new southeastern front. The Russian tanks and armored personnel carriers seen in the area—which would give Russia a land bridge to Crimea—appear to have come straight over the border instead of from separatist-controlled areas in eastern Ukraine, the Los Angeles Times reports. President Petro Poroshenko canceled a trip to Turkey, citing sharp aggravation of the situation in Donetsk region, as Russian troops were actually brought into Ukraine," according to a statement. Russia has not acknowledged any troop movements. A rebel commander says there are around 4,000 Russians fighting with the separatists, but they are all volunteers. "Many former high-ranking military officers have volunteered to join us. They are fighting with us, considering that to be their duty," he tells the BBC. "There are also many in the current Russian military that prefer to spend their leave among us." The US has expressed its "deep concern" about Russian involvement in the rebel offensive. "Russia is clearly trying to put its finger on the scale to tip things back in favor of its proxies," a senior American official tells the New York Times. "Artillery barrages and other Russian military actions have taken their toll on the Ukrainian military." After days of fighting, the strategic southeastern town of Novoazovsk now appears to be under rebel control, the AP reports.