Donald Tusk, the Polish prime minister, put a dent yesterday in US hopes that a deal had been reached on locating a missile defence base in Poland, saying Washington's latest offer was "unsatisfactory."

"In the key matter of the need to increase Polish security we did not reach a result," Mr Tusk said. A day earlier he had spent 40 minutes on the telephone with Dick Cheney, the US vice-president, trying to break the impasse over the base.