Athens  - Riot police clashed with demonstrators outside the US embassy in Athens on Monday during an annual march commemorating the 35th anniversary of a student uprising against the military dictatorship that once ruled Greece.

Some 100 youths wearing masks broke away from a peaceful march of more than 15,000 people through downtown Athens to mark the anniversary of the student uprising against the dictatorship and hurled Molotov cocktails, rocks and sticks at police outside the embassy.

Heavy rainfall quickly extinguished the fires which were set off by the Molotov cocktails and the crowds were quickly dispersed after police retaliated with tear gas.

There were no reports of serious injuries or arrests.

More than 8,000 riot police and undercover officers were deployed in downtown Athens and another 2,000 in the northern Greek city of Thessaloniki.

The streets in downtown Athens have been cordoned off and shops closed early ahead of the march which in past years has been marked with violence.

Students marched from the Polytechnic University in each city to the American embassy to protest Washington's support at the time of the military junta.

Thousands of people, many of them students, entered the campus of Athens Polytechnic University to lay flowers in memory of the dozens of students thought to have died when tanks crushed a pro-democracy uprising in 1973.

There are no official records of the death toll from the events on November 17, 1973. (dpa)