US President George W Bush flies to Europe on Wednesday for a visit designed to bolster support for US military action, but which is in danger of being overshadowed by street protests.

We have indications from a variety of sources that violent left-wing extremists will attempt disruption

Police spokesman Carsten Graefe

When Mr Bush arrives in Germany on Wednesday, 10,000 police officers will be on duty to combat the threat of violent demonstrations.

Officials fear that a hard core of 2,000 protesters in Berlin could hijack peaceful left-wing demonstrations.

On Tuesday, about 10,000 protesters took to the streets, mostly to protest against American foreign policy.

The rally, organised by around 240 separate groups, passed off peacefully, although a small march by the coalition Green Party was broken up by radical anti-globalization campaigners.

The police restored order but the BBC's Berlin correspondent Rob Broomby says the incident has highlighted the fear that peaceful protests can easily be a cover for more serious disruption.

Seeking support

Mr Bush - who is also visiting Russia, France, and Italy - is expected to use his European tour to seek support for possible US action against Iraq.

This is a prospect which has caused anxiety among some European governments.

About 10,000 people took part in Tuesday's demonstrations

His visit to Germany will include talks with Chancellor Gerhard Schroeder.

He is also expected to deliver what has been described as an historical speech to the German parliament, the Bundestag, focusing on the war on terror.

More than 100 separate protests, involving more than 200 diverse groups, are planned during his visit to Germany.

The anti-American protesters argue that US foreign policy has already gone too far, and is increasingly unilateral.

The protest "is not against Bush or his visit, but his war policy," said protester Christa Peter, a 46-year-old teacher from Berlin.

"This theory of the 'axis of evil' is dangerous, and allies like Germany need to take this opportunity to warn him."

Huge police presence

Anti-globalisation protests are also expected, and separate action by pro-American demonstrators is planned.

In Berlin, the 10,000-strong force of officers will be the highest number ever deployed for a post-war state visitor.

Bush tour

Wednesday - arrive Germany Thursday - address German parliament, fly to Moscow Friday - meet Putin, sign arms control treaty Saturday - visit St Petersburg Sunday - fly to Paris, meet Chirac Monday - visit French US war cemetery, travel to Rome, meet Pope Tuesday - Nato summit, return home

"We have indications from a variety of sources that violent left-wing extremists will attempt disruption either from within the rallies or at locations out of the city centre," police spokesman Carsten Graefe said.

"The police are ready. We will be on red alert. There will be massive areas closed off...so that there will be no danger to the state's visitor."

Sewers are being welded shut, police divers will search waterways for hidden explosives, and large areas around government buildings will be completely closed to the public. Airspace is also being closed.

German Foreign Minister Joschke Fischer backed the right of people to protest peacefully, but appealed for violence to be avoided.

"It is in everyone's interest that the demonstrations remain peaceful, otherwise the message transported will be different from the one intended," Mr Fischer said on German Radio.

President Bush has been accused of unilateralism

"Ugly anti-American images would be sent across the Atlantic."

And Chancellor Schroeder warned that police would deal firmly with violence.

"Anyone who confuses the freedom to demonstrate with brawling will run into the decisive and very hard resistance of the police," Mr Schroeder told the Welt am Sonntag newspaper.

Mr Bush will be in Germany until Thursday, staying at a luxury hotel on the Unter Den Linden in what was East Berlin.

He will travel on to Moscow on Thursday afternoon.

His six-day trip will culminate in a Nato summit in Italy.