BEIRUT — President Bashar Assad has exploited his greatest advantage in the Syrian civil war — his air power — to push back rebel advances and prevent the opposition from setting up a rival government in its northern stronghold.
Along the way, fighter jets and helicopters have hit civilian targets such as hospitals, bakeries and residential buildings, according to a report released Thursday by a U.S.-based human rights group. It accused the regime of committing war crimes with indiscriminate airstrikes that have killed more than 4,000 civilians since summer.
The Human Rights Watch report said Assad's air force has dropped "imprecise and inherently indiscriminate" munitions, including cluster bombs, on civilian areas.
In recent months, large parts of northern Syria near the border with Turkey have fallen to the rebels, including several neighborhoods of Aleppo, the country's largest city. With the recent influx of more advanced weapons and other foreign aid, the rebels have also made major gains in the south, seizing military bases and towns in the strategically important region between Damascus and the border with Jordan.
Two years into the uprising, however, the Assad regime's control of the skies is hampering rebels' efforts to hold on to territory they capture with any efficiency. An interim leader of the opposition has been elected, but he and others opposed to Assad have made only a few, brief forays into rebel-controlled areas.
"The air force is extremely important for Assad right now," said Joseph Holliday, a Syria analyst at the Washington-based Institute for the Study of War.
"It has allowed Assad to prevent rebels from establishing a part of Syria where people can be safe and the opposition can focus on governing the place," he said. "It very difficult to do that without a space that is free from constant harassment from the aircraft."