The Obama decision Thursday replaced the Bush administration anti-missile plan with a reconfigured system focused on short- and medium-range missiles. Putin and other Russian officials who spoke to reporters Friday did not say whether Russia would respond with concessions to the United States, particularly on the issue of Iran's nuclear program and its overall military capabilities.

The Obama administration has indicated that it believes Iran has made significant strides in recent months in developing a nuclear weapon, but Russia, which has veto power in the U.N. Security Council, has resisted increasing sanctions against Iran.

Speaking in Washington Friday, Secretary of State Hillary Rodham Clinton kept up the diplomatic pressure, saying that talks next month between Iran and major powers concerned over its nuclear strategy represented a choice for Tehran and that there would be consequences for choices made.

"There will be accompanying costs for Iran's continued defiance: more isolation and economic pressure, less possibility of progress for the people of Iran," Clinton told an audience at the Brookings Institution.

The Russian officials did indicate that the Kremlin would withdraw its threat to base short-range missiles on Russia's western border, in Kaliningrad.

Also on Friday, in another sign of warming relations, NATO's new secretary general, Anders Fogh Rasmussen, called for new cooperation between the alliance and Moscow, including possible coordination between anti-missile systems.