BEIRUT // Syrian troops clashed with rebels in the city of Aleppo for a second day Saturday, forcing inhabitants to flee to safer areas in some of the fiercest fighting to date in the heart of the country's northern commercial hub, activists said.
Until recently, Aleppo, Syria's largest city, has remained largely loyal to President Bashar Assad and has been spared the kind of daily bloodshed that has plagued other cities over the course of the uprising against him.
The fighting in the Salaheddine district in the city center suggested Assad was losing his grip on one more traditional bastion of support.
"This night was very bad, there were huge explosions and the gunfire didn't stop for several hours," said Aleppo-based activist Mohammad Saeed via Skype.
He said dozens of fighters from the rag-tag Free Syrian Army entered Aleppo from the countryside and were now fighting regime troops from inside.
The clashes began Friday and continued throughout the night until Saturday morning, most of it in Salaheddine.
"The uprising has finally reached Aleppo," Saeed said.
This week, fierce fighting between troops and rebels reached the Syrian capital, the central bastion of Assad's rule, shattering parts of the city and sending thousands of people fleeing to neighboring Lebanon and Iraq.
Activists and residents reported a tense calm in Damascus Saturday but said sporadic gunfire and explosions could be heard throughout the night.
Two residents who did not want to be identified for safety reasons said by telephone that the fighting peaked between 1 a.m. and 3 a.m. local time.
Damascus and Aleppo are both home to elites who have benefited from close ties to Assad's regime, as well as merchant classes and minority groups who worry their status will suffer if Assad falls.
But for months, rebels have been gaining strength in poorer towns and cities in the Aleppo countryside, gaining footholds near the Turkish border. Anger has also been building inside the city at the government's deadly crackdown on the uprising and in recent months, it has seen huge anti-government demonstrations, particularly among students at Aleppo University.
In May, Syrian forces stormed student dormitories during an anti-government protest at the university, firing tear gas and bullets in an hours-long siege that killed four students and forced the closure of the state-run school.
The Local Coordination Committees activist network and the Britain-based Syrian Observatory for Human Rights said Friday's fighting in Aleppo forced many residents to flee to safer areas.
An amateur video posted online by activists showed Aleppo residents walking carrying bags of belongings or packing into cars and driving away.