BEIRUT – Al Qaeda's Syrian affiliate and other radical Islamic factions launched an assault Wednesday on a government intelligence building in the northern city of Aleppo, blowing up part of it before trying to storm the facility amid heavy fighting, activists said.
The Aleppo Media Center and the Britain-based Syrian Observatory for Human Rights said a massive blast hit the Air Force Intelligence branch in the Zahra district on the western edge of the city. Air Force Intelligence is one of the most feared security services in the country.
The Observatory said the assault began with the rebels detonating explosives placed in a tunnel dug under the security building. Rebels have used similar tunnel bombs in the past as a way an effective means overcoming their limited firepower compared to government forces.
"Part of the building was destroyed. This was a very big explosion. People very far away could hear it," Observatory director Rami Abdurrahman said. "Clashes are still taking place. The Syrian regime is hitting the area with airstrikes."
He said 20 government troops and 14 militants were killed in the attack, which was led by the Al Qaeda-linked Nusra Front and other radical Islamic armed groups.
A Twitter account run by the Nusra Front in Aleppo province said its fighters and other factions "are breaking into the Air Force Intelligence and surrounding buildings."
There was no information from Syrian state media about the attack.
Aleppo, once Syria's largest city and commercial capital, has been divided between opposition fighters and government troops since mid-2012. Heavy fighting over the past two years has destroyed much of the city, including its historic heart, centered around the ancient citadel.
The U.N. envoy to Syria is trying to broker a local truce Aleppo, although his plan for a "freeze" has been greeted with skepticism by rebels, activists and analysts.
Syria's conflict, which began as an uprising against embattled President Bashar Assad, has killed more than 220,000 people since it began in March 2011. Iran has played a major role in keeping Assad in power, supplying weapons, advisers and cash.
On Wednesday, activists and Iranian media said the commander of a Shiite Afghan faction was killed last week in clashes with Syrian rebels.
The Iranian conservative news website, rajanews.com, said Ali Reza Tavasoli, who led the Fatimiyoun Brigade, was killed Saturday south of the Syrian capital, Damascus.
It said Tavasoli was trusted by Iran's Maj. Gen. Ghasem Soleimani, commander of the Revolutionary Guard's elite and secretive Quds Force.
Ahmad al-Masalmeh, a Syrian opposition activist based in the southern city of Daraa, said Wednesday that Tavasoli and other fighters were killed on the strategic Green Hill, which links the southern suburbs of Damascus with the country's Daraa and Quneitra regions.
Shiite fighters from the region are widely known to be fighting on the side of Assad's forces.