BEIRUT -- Mortar shells crashed into an outdoor cafe at Damascus University on Thursday, killing at least 10 students in the deadliest of a rising number of mortar attacks in the heart of the Syrian capital.
The strikes have escalated as rebels fighting to topple President Bashar Assad try to enter the city, terrifying civilians whose support the opposition needs to advance its cause.
It was unclear who fired the rounds. The government blamed "terrorists," its blanket term for those fighting Assad's regime. Anti-regime activists accused the regime of staging the attack to turn civilians against the rebels.
Mortar strikes on Damascus are relatively new in Syria's crisis, which began in March 2011 with protests calling for Assad's ouster, then evolved into a civil war. The U.N. says more than 70,000 have been killed.
Since February, mortar shells have hit previously safe parts of the capital with increasing frequency.
Some shells appear aimed at government targets, such as one of Assad's palaces and the general command of the Syrian army. Others have hit near civilian targets.
Elizabeth O'Bagy, who studies the Syrian rebels, said it appeared to fit the regime's pattern of escalation.
"Because of the fact that it does follow regime behavior, it is more likely to be a regime attack," she said, while acknowledging it could also have been a rebel misfire.