© Yiorgos Karahalis, ReutersRiot police secure the U.S Embassy in Athens, November 17, 2011, during a rally marking the anniversary of a 1973 students uprising against the dictatorship then ruling Greece and to protest against the U.S. for having supported the 1967-1974 military junta.
Some 30,000 people took to the streets in Athens in commemoration of the 38th anniversary of the ultra-right junta of the "Black Colonels" on Thursday, police said.

Several demonstrations in Athens poured together and joined one mass peaceful demonstration against Greece's government decisions on austerity measures to receive loans from the European Union and the International Monetary Fund.

The protestors were marching toward the U.S. Embassy because the ultra-left organization blames the United States for supporting the "Black Colonels" in their suppressing a university students' uprising on November 17, 1973. During the uprising in 1973, several youth were killed and thousands were injured.

Most of the protestors on Thursday were made up of communists who demand Greece secede from the eurozone and that communism be reinstated in the country.

Several hundred protestors attempted to storm the U.S. Embassy but were stopped by police, after which tensions grew between the two opposing sides and involved Molotov cocktails from the protestors and tear gas from the police. The protestors then blocked the main street with burning garbage bins. Police detained 89 individuals and arrested 11 of them. Four police officers were injured in the incident.

Up to 15,000 protestors also gathered in Thessaloniki.

The "Black Colonels" outlawed all political parties, introduced widespread censorship, disolved dozens of democratic organizations and apprhended their property. Worker strikes were also deemed illegal.