Mortar fire killed at least 15 students in Damascus on Thursday, with state media blaming "terrorists," as an MP from the southern province of Daraa painted a bleak picture of the situation there.
The Damascus University attack came as battles raged between insurgents and loyalist troops in districts on the edges of the city, and as warplanes targeted rebel enclaves in Irbin and other towns east of the capital.
"A total of 15 students were killed in a mortar attack launched by terrorists targeting the architecture faculty," said Damascus University dean Amer Mardini, quoted by the official SANA news agency.
The regime uses the term "terrorists" for rebels who are increasingly targeting President Bashar al-Assad's seat of power.
SANA said six other people were wounded by mortars targeting the faculty cafeteria.
Pro-regime Al-Ikhbariya television ran footage of a bloodied patio filled with broken glass and upturned chairs, and showed doctors treating seriously wounded young people, some of them unconscious.
The national student union denounced the "cowardly terrorist attack that targeted the architecture faculty of Damascus University," state television said.
Rebels battling Assad's regime have stepped up mortar attacks on central Damascus this year, including Umayyad Square which houses state television's headquarters.
The Syrian Observatory for Human Rights, a Britain-based monitoring group that relies on sources on the ground for its information, called for an immediate end to mortar attacks on Damascus.
"The vast majority of people killed in the mortar attacks on Damascus have been civilians," its director Rami Abdel Rahman told AFP.
US State Department spokeswoman Victoria Nuland said it remained unclear who was behind the attack.
But she urged both sides to be "absolutely vigilant in avoiding attacks on civilians and to ensure that their actions are in accordance with international law."
Meanwhile, Syrian Daraa MP Walid al-Zohbi, in an unusual outburst broadcast live on state television, said insurgents have seized large parts of the south.
"Syria is no longer going through a crisis. It is plunged in total war. Terrorism has spread in Syria and so has chaos. This is reality, and all Syrians know it," he told parliament.
Zohbi said the military has withdrawn from many positions and "terrorists from Al-Nusra Front have taken their place," he added of the jihadist group classed by Washington as "terrorists".
Some MPs tried to silence Zohbi, but he refused to be interrupted.
"From the south, we are totally exposed. We are only protected from the west, by Base 61. The people are living in hell and their morale has hit rock bottom," he raged.
Zohbi said he had told senior officials where the insurgents were based, "but there have been no results so far".
Thursday's carnage at Damascus University comes just over two months after a bloody rocket attack killed more than 80 civilians at Aleppo University, the country's second largest institution of higher education.
"Neither the rebels nor the regime should target centres of education. What we saw today in Damascus is a war crime," Abdel Rahman said.
Fighting also raged on the outskirts of Damascus, despite an all-out army attempt to crush the insurgency, the Observatory said.
The neighbourhoods of Qaboon in the northeast, Yarmuk and Al-Hajar al-Aswad in the south and Qadam in the southwest were all affected.
The air force unleashed new strikes on Irbin, Deir Salman and Nashabiyeh east of Damascus, the Observatory said.
It gave a toll of 104 people killed on Thursday, including the 15 at the university.
More than 70,000 people have been killed in Syria's spiralling conflict and millions more have been displaced, the UN says.
On the political front, Russia said it will strongly oppose any bid to give Syria's UN seat to the rebels. Moscow's UN envoy Vitaly Churkin said recognising the Syrian National Coalition would "undercut the standing of the UN."
And Nuland said Washington's "undestanding" was that Syrian opposition chief Ahmed Moaz al-Khatib, who surprised everyone by resigning his post on Sunday, will complete his six-month term before stepping down.