Iranians chanted anti-American slogans on Friday at mass rallies marking the anniversary of the 1979 seizure of the U.S. embassy.

Some demonstrators gathered in Tehran at the former site of the embassy, which they now call the “den of spies.”

Iranian state news reports say some demonstrators used the annual rally to show solidarity with the Arab Spring revolutionary uprisings that have spread across the Middle East and North Africa. Also, some participants voiced support for the Occupy Wall Street movement in the United States.

In 1979, Iranians students stormed the U.S. embassy compound. They held 52 Americans hostage for more than a year to protest U.S. policies. The incident prompted Washington to cut diplomatic ties with Tehran.

Tensions heightened between the two countries after the U.S. announced an alleged Iranian plot to assassinate the Saudi Ambassador to the United States. Iran denied the allegations and demanded a U.S. apology.