( BBC ) - Russia has called on the US to "freeze" plans to employ missile defence facilities in eastern Europe.
Foreign Minister Sergei Lavrov made the call after high-level talks in Moscow with US counterparts.
US Secretary of State Condoleezza Rice insisted the missile defence shield was no threat to Russia, and that the US wanted both countries to work together.
Earlier, however, Russian President Vladimir Putin signalled he would not support American plans.
He urged Washington "not to force" a planned deployment of a radar in the Czech Republic and interceptors in Poland on Russia.
Moscow sees the US plans as a threat to Russia's security.
Mr Putin also threatened to abandon a key nuclear missile treaty which he said was outdated.
Analysts say President Putin's threat to withdraw from the treaty is yet another diplomatic move to pressurise the Americans.
The Russian leader appeared to mock the US plan for a European missile defence system.
"One day you and I may decide that missile defence systems can be deployed on the Moon," Mr Putin said as he began talks with Ms Rice and US Defence Secretary Robert Gates.
"But before we get there, the possibility of reaching an agreement may be lost because you will have implemented your own plans," he said.
The Kremlin has asked the US why it cannot instead use Russian-operated early warning radar in Azerbaijan.
US officials said the Azerbaijan radar was not an alternative because it only offered a broad view of the horizon, and not the narrow focus of the proposed Czech Republic radar.
President Putin said at the start of the talks that it would be difficult to remain part of the Intermediate Range Nuclear Forces (INF) treaty unless it was expanded to include more countries than just the US and Russia.
The reason, he said, was that other countries were developing these kinds of weapons systems - including those close to Russia's borders.
It is not clear which countries he was referring to, but one analyst told the BBC it could mean Iran and North Korea.
The INF treaty, which limits US and Russian short and medium range missiles, was signed 20 years ago and led to the elimination of almost 3,000 Russian and American missiles. Russia has also threatened to leave the Treaty on Conventional Armed Forces in Europe if it is not ratified by all Nato nations.
The US says it needs a missile defence system to counteract "rogue states" like Iran and North Korea.