More than 20,000 demonstrators have joined a peaceful rally in Athens marking the 41st anniversary of a deadly student uprising against the country's former dictatorship.

The annual rally to the U.S. embassy was policed by some 7,000 officers, deployed to prevent a potential repeat Monday of violence seen in previous years.

The 1973 Polytechnic Uprising challenged the dictatorship, and police and the army responded by opening fire against demonstrators and bystanders around a central Athens campus. The regime collapsed the following year.

Although anniversary marches protest U.S. backing of the 1967-74 dictatorship, protesters at more recent rallies have also voiced anger at harsh ongoing austerity measures in the bailed out country.