U.S. President Barack Obama said halting the nuclear weapons threat from Iran would reduce the need for a planned missile defense shield in Eastern Europe. But Mr. Obama denied he has told Russia he will rethink the missile shield program if Moscow puts pressure on Tehran.
The president said he brought up areas of mutual concern in a recent letter to Russian President Dmitri Medvedev - including missile defense and Iran's nuclear ambitions.
"What we had was a lengthy letter talking about a whole range of issues - from nuclear proliferation to how are we going to deal with a set of common security concerns," he explained.
But Mr. Obama denied U.S. news reports that said he told the Russian leader that he would rethink the missile shield if Moscow got Tehran to stop developing nuclear and long-range weapons.
The president said there was no offer of action in the letter.
"It was simply a statement of fact that I have made previously, which is that the missile defense program, to the extent that it is deployed, is designed to deal with, not a Russian threat, but an Iranian threat," said the president.
Washington's plan to deploy missile interceptors in Poland and a radar installation in the Czech Republic has angered Moscow.
President Medvedev has said he is expecting some specific proposals from the Obama administration. And the subject is likely to be on the agenda when Russian Foreign Minister Sergey Lavrov meets Secretary of State Hillary Clinton in Geneva on Friday.
Speaking at the start of a meeting at the White House with British Prime Minister Gordon Brown, President Obama appeared optimistic that U.S- Russia relations will improve on his watch.
"My hope is we can have a constructive relationship where based on common respect and mutual interests we can move forward," he said.
At the Pentagon, Secretary of Defense Robert Gates talked about the need for Washington and Moscow to work together on Iran. He again raised the possibility of Russian cooperation on the missile defense program.
"The reality is that the missiles the Iranians are testing can reach a good part of Russia as well as Eastern Europe and part of Western Europe. The missiles cannot reach the United States yet. This is part of our commitment to a European missile defense," he said.
Gates stressed that the Obama administration's policies on Europe, Russia and missile defense remain under review.
President Obama has said he supports deployment of a missile shield, only if it would be effective and affordable.