ATHENS, Greece (AP) — Thousands of Greece protesters marched Thursday to the U.S. embassy in Athens, in an annual commemoration of a 1973 student uprising that was crushed by the military dictatorship which ruled the country from 1967-74.

About 3,000 police were deployed in central Athens to guard against potential violence, which has frequently broken out in previous years. Before the march started, suspected anarchists stole two riot police shields and helmets and hung them on a statue.

An anti-American protest Tuesday during a visit by President Barack Obama to Athens was marred by extensive clashes between anarchists throwing petrol bombs and stones and Greek riot police.

Many Greek left-wing supporters still deeply resent the U.S. support for the oppressive dictatorship in Greece at the height of the Cold War.

The march Thursday began at the gates of the Polytechnic University complex, where in 1973 the military had sent a tank crashing in to suppress a pro-democracy uprising. Several people were killed during the crackdown, but historians still disagree on the precise death toll.