BEIRUT, (Reuters) – Syrian authorities said on Sunday they had restored order at a military jail near Damascus after a riot, but dissidents said the insurrection was not over and dozens of prisoners had been killed.

The riot broke out on Saturday at Sidnaya prison, a huge complex 30 km (19 miles) northwest of the capital that houses thousands of criminals, political prisoners and soldiers convicted of violating military rules. “Several prisoners convicted of extremism and terror crimes created chaos … The issue required the interference of anti-riot units to restore calm,” the Syrian state news agency said.

The agency did not say whether there were any casualties. The Syrian Observatory for Human Rights, an organisation based in London, said Syrian security forces had killed dozens of prisoners during the riot.

The Observatory said Islamist prisoners, many of whom have been held at Sidnaya for years without trial, started the riot.

It quoted witnesses as saying a hospital near the prison was filled with the wounded.

Syrian dissidents based in Beirut said prisoners were still rioting and security forces remained heavily deployed around the prison.

Syria, which has been ruled by the secular Baath Party since 1963, holds thousands of Islamists and other political prisoners, including writers and human rights advocates.

International human rights groups say random arrests and torture are common.