Former Solidarity leader Lech Walesa said he had expected that the Obama administration would drop the missile defence plan.

'The Americans always cared about their (own) interests. They used everybody else,' Walesa said. 'It wasn't that the shield was that important, but it's about the way. The way of treating us.'

The Polish media appeared to complain that the Czechs had been informed first of any possible cancellation. 'The Czechs already know,' said a headline on news website tvn24. 'The American delegation is barely on its way to Poland.'

Moscow reacted cautiously to the report, with a spokesman for the Russian 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 had 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.