President Hassan Rohani called for engagement with the world in an address Tuesday marking the 35th anniversary of Iran's Islamic Revolution.

"Iran is determined to have fair and constructive talks based on international law. We expect the same willingness on the other side," Rohani said during a ceremony at Tehran's Azadi Square.

The negotiations over Tehran's nuclear program "are a historic test for Europe and the United States," the president said, adding that if the West respected the Islamic Republic's rights it would receive "a positive and appropriate response."

If the world's powers, however, try to use the "incorrect and not very agreeable methods used in the past," they should know that their actions will be "to the detriment of their own nation, of the region and of global welfare and stability," Rohani, a moderate Shiite cleric, said.

Thousands of people gathered in the square early Tuesday for the celebration, but hundreds of those in the front surprisingly filed out as Rohani started speaking.

Several of those leaving the square told Efe they had been instructed by organizers to leave.

Millions of people participated in marches in more than 930 cities across Iran to mark the anniversary of the 1979 Islamic Revolution, chanting "Unity," "Death to America" and "Death to Israel," the official IRINN news channel reported.

A military band, groups of schoolchildren and women covered with the traditional black chador filed into Azadi Square, which was filled with Iranian flags and photographs of Ayatollah Ruhollah Khomeini, the Islamic Republic's founder, and Ayatollah Ali Khamenei, the current supreme spiritual leader. EFE