BEIRUT Syrian rebels stormed a government intelligence complex in the oil-rich east of the country on Tuesday, freeing at least 11 people held in a prison at the facility, activists said.

After five days of heavy clashes around the intelligence compound in the city of Deir el-Zour, rebels finally overran the complex early Tuesday following intense fighting overnight, the Britain-based Syrian Observatory for Human Rights said. Opposition figures were reportedly being held at the jail on the complex’s grounds, but it was not immediately clear whether those freed Tuesday are fighters or activists.

Government forces responded to the rebel advance by unleashing a series of air strikes on the compound, trying to push the opposition fighters from the facility.

Meanwhile, the Observatory said at least 56 bodies were found with their hands bound and gunshots to the head in the northern city of Aleppo. Video posted online by activists showed dozens of mud-covered male bodies laying next to a river. They appeared to be all adults. It was unclear who killed the men and dumped their bodies. Both the Syrian government and the rebels have been accused by human rights groups of committing atrocities during the war, including mass executions. According to the Observatory, as many as 80 bodies might have been dumped at the site in Aleppo.

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Also Tuesday, regime warplanes also carried several air strikes on rebel positions in restive towns and villages around Damascus, including eastern Ghouta and Yalda, and hit other suburbs with artillery, the Observatory said. The group relies on the reports from activists on the ground.

After capturing several major army bases and government outposts, the rebels control large swathes of land in northeastern Syria. Assad’s troops, however, continue to hold a tight grip on the capital after nearly two years of conflict.

The areas on the capital’s doorstep have been rebel strongholds since early on in the revolt. In recent months, the rebels have used them as a base from which they have been trying to push into central Damascus, the seat of Assad’s power.

Rebel factions and opposition activists have long complained over the level of international support they have received from the West. The United States announced Tuesday an additional $150 million in humanitarian aid, but the Obama administration has refused to provide any weaponry to the rebels, citing concerns about fueling the violence — and over the motivations of some of the hardline Islamic rebel groups.

“The U.S. has done a lot, we’re playing a leading role in many ways,” U.S. Ambassador to Syria Robert Ford told CBS News on Monday. “We have substantially tightened the financial squeeze on the regime… and at the same time we’re providing vital humanitarian assistance.”

“The opposition is actually making steady advances,” Ford told CBS News correspondent Clarissa Ward. “Two weeks ago, the regime lost its largest air base. There is fighting in the capital. The regime is little by little, steadily losing its grip on the country.”

Ford said he couldn’t predict how long Assad will remain in power, and that, “ultimately, we have to let these societies find their ways… Americans can’t fix these problems for them, Syrians have to fix it.”

Deir el-Zour has been the scene of heavy fighting since the uprising against Syrian President Bashar Assad began in March 2011. The province, which goes by the same name as the city, is located along Syria’s border with Iraq and includes several oil installations that the rebels have repeatedly targeted.

The aid group Doctors Without Borders said last month that government forces are shelling and 부천출장마사지 bombing Deir el-Zour almost daily. It said tens of thousands of Syrians, many of them wounded, remain trapped in the city.