Protesters riot at British Embassy

The demonstration stood in stark contrast to statements made by British government officials that they were looking for new ways to resolve the crisis peacefully.

Several dozen policemen prevented the protesters from entering the embassy compound, although a few briefly scaled a fence outside the facility's walls before being pushed back.

The protesters chanted "Death to Britain" and "Death to America" as they hurled stones into the courtyard of the embassy. They also shouted "the British spies should be tried".

In speeches made before the students turned on the compound, they demanded the Iranian government expel the British ambassador and close down the embassy, calling it a "den of spies".

In London, a small group of protestors staged an impromptu demonstration outside the Iranian embassy, calling for the military personnel to be freed.

Britain and Iran are at a stand-off over eight British sailors and seven marines who were kidnapped by Iranian naval units on March 23 while patrolling for smugglers near the mouth of the Shatt al-Arab, a waterway that has long been a disputed dividing line between Iraq and Iran.

Britain said they were in Iraqi waters when detained, but Iran has contended the Britons entered its waters illegally.

A British Foreign Office spokeswoman said the demonstration had not caused damage to the embassy and diplomats inside continued to work. "There is a police presence outside and there is no risk to those inside," she said.

US President George Bush called for the release of the sailors and marines, labelling their capture "inexcusable behaviour".