Two explosions tore through one of Syria's biggest universities on the first day of student exams on Tuesday, killing 83 people and wounding dozens, a monitoring group said.
Bloodshed has disrupted civilian life across Syria since a violent government crackdown in early 2011 on peaceful demonstrations for democratic reform turned the unrest into an armed insurgency bent on overthrowing President Bashar al-Assad.
More than 50 countries asked the United Nations Security Council on Tuesday to refer the crisis to the International Criminal Court, which prosecutes people for genocide and war crimes. But Russia - Assad's long-standing ally and arms supplier - blocked the initiative, calling it "ill-timed and counterproductive.
Each side in the 22-month-old conflict blamed the other for Tuesday's blasts at the University of Aleppo, located in a government-held area of Syria's most populous city.
Some activists in Aleppo said a government attack caused the explosions, while state television accused "terrorists" - a term they often use to describe the rebels - of firing two rockets at the school. A rebel fighter said the blasts appeared to have been caused by "ground-to-ground" missiles.
The Syrian Observatory for Human Rights, a Britain-based monitoring group, said 83 people were killed and dozens wounded, but it could not identify the source of the blasts.
"Dozens are in critical condition," the Observatory said in a statement, citing doctors and students.
State television showed a body lying on the street and several cars burning. One of the university buildings was damaged.
Video footage showed students carrying books out of the university after one of the explosions, walking quickly away from rising smoke. The camera then shakes to the sound of another explosion and people begin to run.
"A cowardly terrorist act targeted the students of Aleppo University as they sat for their mid-term examinations," Syria's United Nations ambassador, Bashar Ja'afari, told the U.N. Security Council in New York. He said 82 students had died and 162 more were wounded.
If confirmed, the government's report of a rocket attack would suggest rebels in the area had been able to obtain and deploy more powerful weapons than previously used.
The nearest rebel-controlled area, Bustan al-Qasr, is more than a mile away from the university.
Activists rejected the suggestion that insurgents were behind the attack, however, and instead blamed the government.
"The warplanes of this criminal regime do not respect a mosque, a church or a university," said a student who gave his name as Abu Tayem.
GRINDING TOWARD STALEMATE
The rebels have been trying to take Aleppo - once a thriving commercial hub - since the summer, but have been unable to uproot Assad's better-armed and more organized forces.
International efforts to find a political solution to Syria's civil war have similarly resulted in stalemate, even as the conflict's death toll surged above 60,000.
The crisis has driven hundreds of thousands of people to flee the country, many to neighboring Jordan, Lebanon and Turkey, where a fire at a camp in the country's southeast killed a pregnant Syrian woman and her three children on Tuesday.
Inside Syria, neither the military nor the insurgents have been able to sustain clear momentum.
The rebels remain poorly equipped and disorganized compared with Assad's forces, despite winning support from some regional powers like Turkey and Saudi Arabia.
The government also benefits from superior air power, used to pummel rebel-held areas around Damascus and elsewhere.
Rebel efforts to assault the capital also appear to have ground toward a stalemate. A witness in a rebel-controlled district of Damascus said on Tuesday the front line between the two sides was quiet.
The streets were still full of civilians, the witness said, despite the sound of shells hitting nearby buildings. He said people were walking around, buying sweets and sandwiches.
(Additional reporting by Oliver Holmes in Beirut and Steve Gutterman in Moscow; Writing by Alexander Dziadosz; Editing by Mark Heinrich)