Syria's state-run news agency SANA reported Thursday that the students were killed when the mortar rounds hit the university's College of Architecture cafeteria, located in the central district of Baramkeh, near several government buildings including the Defense Ministry.

"A total of 15 students were killed in a mortar attack launched by terrorists targeting the architecture faculty," university dean Amer Mardini was quoted as saying by SANA.

The pro-government TV channel Al-Ikhbariya showed images of doctors trying to resuscitate at least two young men, as well as a bloodied patio that appeared to be an outdoor cafeteria.

Syria's National Students Union immediately condemned the violence, calling it a "cowardly terrorist attack."

The Syrian Observatory for Human Rights, a Britain-based activist group with links to the opposition, also reported the attack, but put the death toll at 13 people.

There was no immediate claim of responsibility for the attack.

Thursday's violence comes a day after at least 148 people were killed in fighting across the country, the Observatory added. More than 70,000 people have been killed and millions displaced in Syria's two-year civil war, the United Nations reports.

Turkey denies refugee deportation

The Turkish Foreign Ministry said Thursday it did not forcibly expel any Syrians, but that around 50-60 people returned to the war-torn country overnight. Some of those who left may have been involved in clashes with Turkish military police Wednesday, but they left on voluntarily, the Foreign Ministry added.

At the Suleymansah camp, near the Turkish town of Akcakale, Syrian refugees Wednesday threw rocks at military police, who fired teargas and water cannon. Witnesses said hundreds of Syrians were bussed to the border after the clashes.

The unrest began after a 7-year-old child was killed in a fire.

The UN's refugee agency, UNHCR, expressed concern over the reports and said it raised the issue with Turkey. Such deportations would be against UN conventions governing the treatment of refugees.

dr/mkg (Reuters, AFP, AP)