The head of the Bahrain Center for Human Rights says he was detained, beaten and questioned by security forces Sunday.
Nabeel Rajab said he was blindfolded, handcuffed and placed in the back of a car. He says he was beaten and threatened before he was released several hours later. He said state security forces also confiscated computers, CDs and mobile phones.
The human rights activist and his center have spoken out about Bahraini authorities' crackdown on anti-government protesters.
At least five people were killed Wednesday when security forces swept through Pearl Square in the capital, Manama. The square has been a rallying point for the thousands of mostly Shi'ite demonstrators who are demanding reforms from the minority Sunni government.
The government declared a three-month state of emergency this week to try to end the protests. Authorities also arrested at least six opposition leaders on charges that include communicating with foreign countries.