An Islamist faction of Syrian rebels captured an infantry base in the northern city of Aleppo, its fighters said Sunday, as forces fighting to topple President Bashar Assad advanced on the country's largest city.

Also Sunday, Syrian warplanes blasted a Palestinian refugee camp near Damascus, killing eight people and wounding dozens, activists said. Some Palestinian groups in the Yarmouk camp have been backing Assad's regime.

The base was the second major army installation taken by rebels in a week in Aleppo. Its fall is the latest blow to the Assad regime.

Last week more than 100 nations, including the U.S., recognized the new Syrian opposition council as the legitimate representative of the country, a boost for the opposition forces that have been bombing regime targets in and around Damascus, once an impregnable stronghold of the Assad regime.

A statement by the al-Tawheed Brigade said the rebels "fully liberated" the military facility in Aleppo on Saturday. It was posted on al-Tawheed's official website on Sunday and said the Islamist rebel brigade's commander was killed in the battle.

The complex, known as Hanano Barracks, includes an army base, a recruiting centre and a military school.

The Al-Tawheed Brigade is one of the largest rebel groups operating in Aleppo, Syria's largest city, which has been a major front in the civil war since July.

One of the videos posted on the group's website shows the body of a man the narrator says is "the hero and martyr who was killed on the day of liberating the infantry school," apparently the Al-Tawheed commander, Col. Youssef al-Jader. A boy said to be the commander's son is seen crying as he leans over the dead man. The uprising started in March 2011 as peaceful protests but quickly turned into a civil war after the government's brutal crackdown on dissent.

Air strikes in capital

Activists say more than 40,000 people have been killed in almost 21 months of conflict that has increasingly sectarian overtones.

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A Free Syrian Army fighter aims his weapon in Aleppo. The Al-Tawheed Brigade is one of the largest rebel groups operating in the city. (Saleh Anadani/Reuters)

The opposition fighters mostly come from Syria's majority Sunni Muslim community. Assad's regime is dominated by members of the Alawite sect, an offshoot of Shiite Islam.

On Sunday, fighter jets screamed over Damascus to bomb two areas in the southern part of the capital.

The Britain-based Syrian Observatory for Human Rights said fighter jets carried out six airstrikes the Hajar Aswad area and the neighbouring Yarmouk Palestinian camp, where the rebels have been advancing.

Eight people were killed in the airstrike on Yarmouk, the Observatory said, and dozens were wounded. At least three people were killed in the clashes between rebels and gunmen loyal to Assad that followed the air strike, said Rami Abdul-Rahman, the Observatory's president.

The Observatory relies on reports from activists on the ground.

A Yarmouk resident, who observed the fighting from the edge of the camp, spoke on condition of anonymity for fear of reprisals.

"There is a lot of fire all over, after the bombs were dropped on Yarmouk," he told the AP. "People are fleeing in all directions to find safety."

An activist video posted online after the attack on Yarmouk shows scattered glass, debris and twisted metal on a narrow street. Gravely injured people are seen lying on the street in pools of blood.

In Ramallah, Palestinian officials blasted the Syrian government for the attack.

"We condemn in the strongest terms the crime of Assad's regime in Yarmouk refugee camp, and call on all international parties, including the states that still back this regime, to act immediately and stop these massacres against Syrians and Palestinians in Syria," PLO official Yasser Abed Rabbo told the AP.

Meanwhile, reports on Sunday also say Syrian warplanes bombed the  town of Azaz close to the Turkish border, destroying several homes and causing hundreds of people to flee.    The Reuters report said the majority of the bombs hit the centre of Azaz, around three  kilometres from the Turkish border in an area  dominated by Syrian rebels. At least one landed 500 metres  from Turkish soil.