Syrian forces have opened fire on thousands of protesters in Aleppo, a day after a raid on dormitories at the city's main university killed four students and forced the closure of the state-run school.
A local activist said the protests were the largest since the start of the uprising against president Bashar Assad in March 2011. There was no immediate word of casualties.
"The people are incensed by what happened at the university," said the activist, Mohammed Saeed. "Everyone wants to express solidarity with those students."
Mr Saeed said security forces were out in force, firing live ammunition to disperse protesters and arresting people randomly. "With our blood, we sacrifice for you students," people shouted.
The raid at Aleppo University was an unusually violent incident for the city, a major economic hub that has remained largely loyal to Assad over the course of the country's 14-month uprising. The attack on a university campus, considered something of a safe space even within Syria's upheaval, sparked outrage among many residents.
Activists said large protests formed on Thursday night in solidarity with students who were thrown out of their dorms along with their belongings. Dozens of protesters were arrested during the night, activists said.
Today, tens of thousands of people demonstrated as they streamed out of mosques in several districts of the city. Friday, the Muslim holy day, is the main day of anti-government protests in Syria, when thousands of demonstrators around the county have been taking to the streets, calling for Assad's removal.
Aleppo University announced it was closing until final exams on May 13 following the siege that began late on Wednesday, when around 1,500 students staged a protest against Assad. Pro-regime students attacked the crowd with knives before security forces swept in, firing tear gas and then live ammunition, activists said.
The Syrian National Council opposition group called for a nationwide university strike in solidarity with Aleppo University, but no classes were scheduled on Friday, the start of the weekend in Syria.
The university incident further highlighted concerns that a peace plan brokered by international envoy Kofi Annan nearly a month ago has done little to stop the bloodshed.