The death toll in the crackdown on nationwide protests in Iran has spiked to at least 538 people, activists said.
More than 10,600 people have been detained, said the US-based Human Rights Activists News Agency.
Of those killed, 490 are protesters and 48 are members of the security forces, it said, warning the toll is likely to go up.
With the internet down in Iran and phone lines cut off, gauging the demonstrations from abroad has grown more difficult.
The activist group, which relies on activists in Iran cross-checking information, has offered accurate tolls in previous rounds of unrest in the Islamic Republic.
The Iranian government has not offered any overall casualty figures for the demonstrations.
The Associated Press has been unable to independently assess the toll, given that internet and international phone calls are now being blocked in Iran.