A human rights group has said it believed that at least 88 people, 10 of them children, have died in detention in Syria during five months of anti-government protests - a dramatic increase that coincides with the government's bloody crackdown.
Some of the victims were as young as 13, Amnesty International said, adding that in recent years the annual number of deaths behind Syrian jails had been about five.
"These deaths behind bars are reaching massive proportions, and appear to be an extension of the same brutal disdain for life that we are seeing daily on the streets of Syria," said Neil Sammonds, Amnesty International's researcher on Syria.
Mr Sammonds also said the group had heard accounts of horrific torture.
The victims, all men or boys, were arrested after mass protests began in March. All the victims are believed to have been detained because they were suspected of being involved in the protests, Amnesty said in a report. In at least 52 of the cases there was evidence that torture or ill-treatment caused or contributed to the deaths, the report said.
Deaths in detention have also been reported in five other areas: Damascus and Rif Damashq, Idlib, Hama and Aleppo, Amnesty said.
Amnesty International has called on the UN Security Council to refer the situation in Syria to the International Criminal Court, to impose an arms embargo on Syria and to freeze the assets of president Bashar Assad and his senior officials.
Meanwhile Syrian security forces searching for anti-government protesters have raided houses in central Syria.
Activists said troops backed by tanks and military vehicles entered districts in Homs and Hama as part of efforts to crush street protests against President Bashar Assad.
The raids come a day after security forces killed seven people as thousands of protesters poured out of mosques and marched through cemeteries at the start of Eid al-Fitr, a holiday when Muslims traditionally visit graves and pray for the dead.