The government's crackdown on protests in Iran has killed at least 538 people, and even more are feared dead, activists said Sunday. At least another 10,600 people have been detained over the two weeks of protests, said the US-based Human Rights Activists News Agency, which has been accurate in previous rounds of unrest in Iran in recent years, the AP reports. The organization relies on supporters in Iran crosschecking information. It said of those killed, 490 were protesters and 48 were members of security forces. The Iranian government has not provided overall casualty figures for the demonstrations.