A Syrian group hacked the official website of the London-based Syrian Observatory for Human Rights watchdog group Thursday, Xinhua reported.
The group, the Syrian Electronic Army (SEA), replaced the observatory's home page with a black screen, with a message describing the head of the observatory, Rami Abdul-Rahman, as an "agent of the British intelligence".
The SEA earlier claimed responsibility for disrupting The New York Times, Twitter and other Western media websites.
The Syrian Observatory for Human Rights, founded in May 2006 as an information office opposed to the Syrian government, has been cited by many Western news outlets on developments inside Syria.