The Washington Post reports: Syrian warplanes bombed the nation’s largest city Tuesday, activists said, a dramatic escalation in the 16-month uprising and a stark sign of the government’s growing desperation as it tries to reverse the recent momentum of rebel forces.

Aleppo, like Damascus, the Syrian capital, had long been seen as a stronghold of support for President Bashar al-Assad. But the unrest has spread to the city, Syria’s commercial capital, in recent days, adding to a sense that the regime is losing control after the assassinations last week of four of its top security officials in a bombing.

Tuesday’s aerial bombing of Aleppo, the first of its kind in the conflict, was part of a coordinated assault by government forces that included heavy artillery shelling and rockets launched from military helicopters. The attacks targeted Tariq Bab, a residential area east of Aleppo, as well as the neighborhoods of Sakhour and Masaken Hanano in Aleppo, according to the Local Coordination Committees, an activist network.

Although helicopter gunships have been used in the past, the government’s decision to deploy fixed-wing aircraft appeared to be an effort to intimidate the rebel forces by signaling that the regime had yet to use its full military arsenal. Syria has one of the largest air forces in the Middle East, and its use in battling the rebels could give the government a critical advantage over a rebel force that has struggled to acquire heavy weapons.

The BBC’s Ian Pannell, reporting from Aleppo confirms that the Syrian air force is now bombing Syria’s largest city:

Helicopter gunships spun through the skies throughout the day, firing bullets and rockets to the ground. Sustained artillery and mortar rounds pounded restive neighbourhoods.

But it was what happened late in the afternoon that underlined the grave risk to the government of losing ground in what is Syria’s largest city and its economic capital.

First came an unmistakeable sound that has so far been absent in this conflict – the roar of fighter jets.

What appeared to be Russian-made MiG planes arced through the sky. We watched as they dropped in, bombing and strafing rebel positions.

Dead and wounded civilians and fighters were taken to hospitals and makeshift clinics as the human cost of this conflict continues to grow.

The stakes for both sides here could not be higher and it is now clear that neither side is prepared to give way.