Between 1,500 and 4,000 people, depending on sources, protested against the war outside a key NATO naval base hosting US ships on Crete near the city of Chania.

Protestors lobbed stones and firebombs at the base and police used tear gas to disperse them.

The organizers of the protest, the anti-globalization Greek Social Forum, erected a large banner outside the base reading: "No to war. Close down the base."

Demonstrators took to the streets of Chania on Saturday and then marched to the base where they camped out overnight.

Left-wing opposition parties have called since the start of the war for the base to be closed. But the government of Socialist Prime Minister Costas Simitis, has said a US-Greek agreement on use of the base by US warships will not be changed.

In Spain, police said 15,000 people attended an open-air concert in central Madrid, under banners reading "music for peace" and "stop the war."

Organizers said at least 500,000 people gathered near the city's Alcala gate to listen to performances by some 20 Spanish artists including Ana Belen and Joaquim Sabina.

"The peace is with us, in the houses, in the streets, in the parliament, in the factories, at the university. No one will make us be quiet," said Spain's top anti-terrorist judge Baltasar Garzon from the stage in between sets.

"To gag a people and take hostage their freedom of speech, is the same as wanting to finish them off," Garzon said.

The concert was one of a string of anti-war efforts -- including legal action against the government -- organised in Spain, where the public overwhelmingly opposes the staunch support for the war by Prime Minister Jose Maria Aznar.

Sunday's concert was organised by the "Culture Against the War" group, the Socialist party's Social Forum, a coalition of far-left parties and the country's two main unions.

It took place at a venue smaller than originally planned, after the city authorities requested a last-minute change of location.

In Bulgaria, some 200 people attended an open-air concert in the capital of Sofia.

SPACE.WIRE