The US appeared today to be preparing to shelve a controversial "missile shield" plan which was to be based in eastern Europe.
President Barack Obama phoned the Czech prime minister and reportedly told him he will scrap the programme.
Mr Obama told Jan Fischer the US intends to "withdraw from its missile defence project in the Czech Republic and Poland," said reports.
The missile shield deeply angered Russia. The plan - originally proposed by the Bush administration - called for 10 interceptor missiles in Poland and a radar system in the Czech Republic.
"It is most probable that the US administration will unfortunately scrap the plan altogether," said Jaroslaw Gowin, a member of Poland's ruling Civic Platform party.
"This would confirm that Central Europe is not in the centre of Obama administration's interest," he said, adding: "But maybe the US will offer us an alternative."
The Czech government had stood behind the planned radar system despite fierce opposition from the public, which has staged numerous protests over the past few years.
Critics fear the Czech Republic would be targeted by terrorists if it agreed to host the radar system, which was planned for the Brdy military installation 50 miles from Prague.
The Bush administration had said the missile shield was a strategic way to counter a threat from Iran or another rogue state in the Middle East.
Russia has expressed outrage over the plan to base US interceptor rockets in countries so close to its territory.