TEHRAN , Iran ( CNN ) -- Iran should be allowed to pursue its nuclear program for peaceful purposes , Russian President Vladimir Putin said on Tuesday during the first visit to the country by a Kremlin leader since 1943 . Putin , right , is greeted by Iranian President Mahmoud Ahmadinejad following his arrival in Tehran . Putin , who is in Tehran to attend a summit of Caspian Sea nations , said that he and the other leaders agreed that `` peaceful nuclear activities must be allowed '' in the region . `` The Iranians are cooperating with Russian nuclear agencies and the main objectives are peaceful objectives , '' he said . Russia is building Iran 's first nuclear power plant and has resisted moves by the U.S. and its allies to impose stronger U.N. sanctions against Tehran . On Monday , U.S. Defense Secretary Robert Gates reiterated the Bush administration 's stance that `` all options '' must be kept `` on the table '' in confronting the threats posed by Iran -- a reference to the option of using military action against the long-time U.S. adversary . `` We should have no illusions about the nature of this regime or its leaders -- about their designs for their nuclear program , their willingness to live up to their rhetoric , their intentions for Iraq , or their ambitions in the Gulf region , '' Gates said in a speech to the Jewish Institute for National Security Affairs . The leaders of Iran , Russia , Kazakhstan , Turkmenistan and Azerbaijan also met Tuesday to reach agreement on issues relating to the sharing and regulating of the Caspian Sea -- the world 's largest inland body of water . Speaking afterwards , Putin said that no Caspian nation should offer its territory to third parties intent on military action against other countries in the region -- a reference to rumors that the U.S. planned to use Azerbaijan as a base for a possible attack against Iran , The Associated Press reported . `` We are saying that no Caspian nation should offer its territory to third powers for use of force or military aggression against any Caspian state , '' Putin said . `` The Caspian Sea is an inland sea and it only belongs to the Caspian states , therefore only they are entitled to have their ships and military forces here , '' added Iranian President Mahmoud Ahmadinejad . Putin , defying reports of an assassination plot against him , was greeted by Iranian Foreign Minister Manouchehr Mottaki as he stepped off his plane at Tehran 's Mehrabad Airport . During a news conference Monday after talks with German Chancellor Angela Merkel in Wiesbaden , Germany , Putin said rumors of an attempt on his life would not stop his plans . `` Of course I will travel to Iran , '' Putin said . `` If I reacted to these kinds of rumors every time , I could never leave the house . '' Iranian officials denied there was an assassination plot against Putin , with a Foreign Ministry spokesman describing rumors of a possible terrorist action during the Putin visit baseless . `` Spreading this kind of totally false news lacks any value and can not damage the trend of the prepared programs , '' spokesman Mohammadali Hosseini told the Iranian FARS news agency . Hosseini blamed the rumor on Western media , particularly the U.S. media , saying the report was `` made up by the enemies of relations between Iran and Russia to create a psychological war . '' Putin 's visit is the first by a leader in the Kremlin to Iran since Joseph Stalin 's World War II conference meeting with U.S. President Franklin D. Roosevelt and British Prime Minister Winston Churchill . `` Putin 's trip to Tehran is a show of Russia 's independence in global affairs . Putin , who approaches the end of his term , wants to demonstrate that he would n't cave in to the U.S. pressure , '' said Alexander Pikayev , an expert on Iran with Russia 's Institute for World Economy and International Relations , in a report carried by AP . Putin 's schedule also includes meetings with Ahmadinejad and Iran 's supreme leader , Ali Khamenei , AP said . E-mail to a friend . Copyright 2007 CNN . All rights reserved.This material may not be published , broadcast , rewritten , or redistributed . Associated Press contributed to this report .
Russian President Putin backs Iran 's ` ` peaceful '' nuclear program during visit . Putin in Tehran to attend meeting of Caspian Sea Commission to discuss human rights . Putin , Russia set to discuss Iranian nuclear program , U.S. push for talks . Putin downplay rumors of nuclear plot ; Iran says claims are ` ` baseless ''