The spokesman said that US Under Secretary of State for Arms Control and International Security, Ellen Tauscher, is planning Thursday to arrive in Prague from Warsaw to provide details.

At the same time, Poland's Deputy Foreign Minister Stanislaw Komorowski confirmed that a meeting over the defence system was to take place in Warsaw Thursday morning.

Moscow reacted cautiously to the report, with a spokesman for the Russia Foreign Ministry saying 'it would be good news for Russia'.

The spokesman went on to say that if the US was indeed reconsidering the facilities, Russia's unease with the project must have been taken into consideration, according to the Interfax news agency.

While the Bush administration insisted that the bases would protect the West against potential long-range missiles from so-called 'rogue' states such as Iran, Moscow saw the project as a threat to its own security.