The Syrian opposition claimed victory in capturing an army artillery base in the eastern province of Deir al-Zor Thursday even as the government warplanes pounded a building in Aleppo, damaging in the process one of the last remaining hospitals that stood nearby.

β€œThe Mayadeen military base fell at 8.30 a.m. (1:30 a.m. Eastern Time)," Abu Laila, an official in the Military Revolutionary Council in the province, told Reuters. He said 44 rebel fighters were killed in the siege of the base.

"The whole countryside, from the Iraqi border and along the Euphrates to the city of Deir al-Zor, is now under rebel control,” he said.

The capture of Deir al-Zor base followed that of a military airport 80 km to the southeast on the Iraqi border last week, Reuters reported.

On Wednesday night, warplanes bombed a building adjacent to the hospital, gutting the building and spraying shrapnel and debris into the nearby hospital, the Associated Press reported citing activists.

The Dar al-Shifa hospital, run by volunteer doctors, nurses and aides to give medical care to both civilians and rebels has incurred significant damage in the aerial attacks by the military planes in recent months.

Rami Abdul-Rahman, chief of the Britain-based Syrian Observatory for Human Rights, told the AP that at least 11 rebels were killed in the airstrike. In addition, a doctor β€” who was later identified by the another opposition activist group Local Coordination Committees (LLC) as Mohammad Qassem Agha β€” and three children, who were on the street, were also killed.

LLC said 40 people died in the airstrikes in Aleppo Wednesday.