Italian Prime Minister Romano Prodi is holding crisis talks over the future of his government after it failed to secure a parliamentary vote of support for its foreign policy.
Massimo D'Alema, the foreign minister, had said before the vote that the centre-left government should resign if it did not command majority support on foreign policy.
The motion in the Senate received 158 votes in favour - below the necessary majority of 160 votes - and was followed by a chorus of opposition calls for the government to "quit, quit, quit".
There is no constitutional requirement for Prodi to step down.
Thousands rally
The government has been forced onto the defensive over its deployment of 2,000 troops in Afghanistan and the enlargement of a US military base at Vicenza in northern Italy.
Both policies are strongly opposed by the left, which is part of Prodi's multi-party government.
D'Alema said that to go back on the approval that the prime minister gave last month for the base enlargement would be a "hostile act" toward the United States.
More than 80,000 people took part in a rally last Saturday in Vicenza against the enlargement.
Prodi's coalition narrowly beat Silvio Berlusconi's conservatives in a general election last year.
His fragile ruling coalition, which ranges from Catholics to communists, has only a one-seat majority in the senate but in the past had managed to win majority support despite divisions by calling confidence votes.