Rioting at a prison near Syria's capital killed at least nine inmates Saturday, according to a human rights activist in phone contact with the prisoners.

Mohammed Abdullah, a Beirut-based Syrian activist, told The Associated Press that rioting inmates called him and informed him of the deaths, using a cell phone belonging to one of the guards they had taken hostage.

Abdullah said he lost contact with them by early evening, and it appeared the phone had been shut off. He said all of those killed were prisoners.

He quoted multiple inmates as saying military policemen had stepped on a copy of the Quran, Islam's holy book, during a routine inspection of the Saidnaya prison early Saturday.

It was unclear whether the Quran incident was intentional, but it angered some Islamists jailed at the facility and sparked rioting, Abdullah said.

The Syrian government did not immediately confirm the incident. Syrian authorities rarely comment on human rights reports or prison conditions.

Another Syrian human rights activist, Muhammad al-Hassani, told the AP by telephone from Damascus that he could see smoke billowing from the prison, and inmates standing on the building's roof. Ambulances were ferrying casualties to a nearby hospital, he said.

Al-Hassani, who heads Syria's National Organization for Human Rights, said phone lines were cut midday Saturday in the area around the prison. Syrian troops were closing off roads, he said.

Al-Hassani could not confirm the Quran incident nor a number of casualties.

The London-based Syrian Observatory for Human Rights confirmed the riot and said on its Web site that 25 prisoners had been killed. It did not explain how it got the figure and did not return calls for comment.