Videos circulating on social media appears to show Iranian demonstrators running away from tear gas and shouting 'Death to the dictator'; another video shows a woman who appears to be shot, bleeding from the leg.

Axar.az reports citing Ynetnews that there was no immediate report in Iranian state-run media on the incident near Azadi, or Freedom, Square in Tehran on Sunday night after a call went up for protests there. However, international rights groups already have called on Iran to allow people to protest peacefully as allowed by the country's constitution.

"After successive national traumas in a short time period, people should be allowed to safely grieve and demand accountability," said Hadi Ghaemi, the executive director of the New York-based Center for Human Rights in Iran. "Iranians shouldn't have to risk their lives to exercise their constitutional right to peaceful assembly."

The crash of the Ukraine International Airline early on Wednesday killed all 176 people on board, mostly Iranians and Iranian-Canadians. After pointing to a technical failure and insisting for three days that the Iranian armed forces were not to blame, authorities on Saturday admitted accidentally shooting it down in the face of mounting evidence and accusations by Western leaders.