Italian riot police tear gas proestors

Italian riot police tonight used tear gas against anti-Bush demonstrators, disrupting an anti-globalisation protest in the centre of Rome.

The violence broke out after US President George Bush had concluded his official business for the day during a visit to Italy and had returned to the residence of the US ambassador.

More than an hour into the clashes, police charged the demonstrators, chasing them down alleyways to break up the crowd as helicopters circled overhead.

News agency Ansa said six people were arrested.

Police said several officers had been injured.

The violence broke out as the protest march reached its destination at Piazza Navona, famed for its Bernini fountain and a favourite tourist spot.

Thousands of police had been deployed around the Coliseum, the Piazza Venezia and other venues and demonstrators had been warned not to cover their faces, carry sticks or other weapons.

Smoke filled a broad boulevard from which violent demonstrators lobbed objects and smoke bombs at police taking cover in an alley.

Demonstrators ran wild in the historic area, kicking in the window of a bank, breaking flowerpots and using the pieces as weapons, overthrowing rubbish bins and spraying graffiti on a nearby McDonald's.

Masked demonstrators wearing black infiltrated the otherwise peaceful protest and used it as cover to hurl objects at police.

Organisers put the crowd in the main demonstration, which earlier marched peacefully through the city behind a banner "No Bush, no war," and beating drums at some 150,000.

Protesters took aim at local and global issues, including the wars in Iraq and Afghanistan, as well as Italy's participation in the latter.

Also targeted was Bush's environmental policies and the planned expansion of a US military base in the north eastern city of Vicenza.

"The US are a threat for their aggressive policies and for the cultural model that they try to export all around the world," said Marco Franchi of Perugia, who carried a banner that read: "God Smash America."

Earlier, before the protest turned violent, White House spokeswoman Dana Perino said Bush had no problem with the demonstrations.

"That's what democracy is all about," Perino said. "He understands not everybody is going to agree with him."