Al-Nusra Front, Al-Qaeda’s affiliate in Syria, on Saturday drove “moderate rebels” backed by the United States out of a strategic northern military base in fierce fighting that left dozens dead, AFP reported.

At least 29 fighters from the Western-armed Hazm movement were killed along with six Nusra Front jihadists, according to the Syrian Observatory for Human Rights.

It said fierce fighting had broken out on Friday night for Base 46, west of the city of Aleppo.

“Al-Nusra captured Base 46,” Rami Abdel Rahman, director of the Britain-based Observatory, told AFP.

Base 46 is a sprawling military compound that rebel fighters seized in November 2012 from Syrian army troops.

In a statement, residents in the nearby rebel-held village of Atareb criticized the attack on the base and appealed to Al-Nusra to instead fight the “infidel regime and its allies.”

The offensive came a month after Al-Nusra expelled Hazm from Regiment 111, another base they had taken from Syrian army forces.

In addition to fighting in Syria, Al-Nusra also joined an incursion into the Lebanese border town of Arsal in August and its fighters captured several Lebanese soldiers when they pulled out. They have shot dead one of them.

Hazm, loosely branded as the Free Syrian Army, was the first to receive U.S.-made anti-tank missiles from its Western backers last year, according to AFP.

Over the four years of the Syrian civil war, small-scale weapons aid and some military training was supplied to selected Syrian rebel groups, along with “non-lethal” aid such as medical supplies and other equipment.

More extensive assistance was mostly ruled out, due to fear that jihadist rebel groups, such as ISIS and the Al-Nusra Front, might get their hands on these weapons. But as ISIS has become stronger in the region, the United States decided to train and equip moderate Syrian rebels as part of the campaign against the jihadist group.