NICOSIA — The Syrian Observatory for Human Rights said on Sunday prominent rights campaigner Najati Tayara is in a "very bad" health condition after he was "severely" beaten at a Homs prison.

The Britain-based observatory said in a statement received by AFP in Nicosia that it "has learned that investigators at the so-called 'Polish' prison in Homs severely beat Tayara on Friday.

"He is in a very bad health condition. He has been moved to the military intelligence division in Damascus," it added.

Tayara, 66, was arrested in Homs on May 12, a day after he reported that shelling and gunfire had rocked the city, the third largest city in Syria.

"He was referred to court on charges of harming the prestige of the state," the statement said, adding that he was released from Homs central prison on August 31 but later arrested by intelligence officials.

"The Observatory holds the Syrian authorities responsible for any danger that threatens the life of Tayara," the rights advocacy group said.

"It condemns the continued arbitrary arrests of opponents and activists, and calls for their immediate release."

The United Nations says more than 2,200 people -- mostly civilians -- have been killed in a crackdown on almost daily protests by pro-democracy and anti-regime demonstrators in Syria since mid-March. Rights groups say more than 10,000 people are behind bars.