TWO days of heavy air strikes by a Western-led coalition have abruptly flipped the momentum of Libya's civil war, particularly in the east of the country. Regular troops loyal to Libya's embattled leader, Muammar Qaddafi, had pressed into Benghazi, the east's main city, on Saturday. By Monday morning they had vanished, leaving a trail of vehicles scorched by air attacks along the 150km stretch of desert road to Ajdabiya, a key road junction captured only last Thursday by Mr Qaddafi's forces. The question now is how soon and how effectively the poorly equipped rebel force can mobilise a westward counterthrust, first to recapture the oil export centres of Brega and Ras Lanuf, and eventually Mr Qaddafi's hometown, Sirte. From there it is another 400km to the Libyan capital, Tripoli.

Furious aerial bombardment by France, America and Britain appears to have destroyed the Libyan regime's air defences and grounded its air force. Planes from Italy, Canada, Spain, Denmark, Norway, Qatar and the United Arab Emirates are also arriving. But Mr Qaddafi's troops have retained control on the ground in most of western Libya. The strategically vital city of Misurata, just 200km east of Tripoli, has been in rebel hands since the outbreak of fighting last month, but now faces an accelerated onslaught by besieging loyalist forces, which have also intensified shelling of a rebel-held mountain region south-west of Tripoli. Should these pockets fall, Mr Qaddafi will have succeeded in consolidating his hold of the west of the country, enabling him to mass forces to resist the expected main rebel advance from the east.

As the roadside carnage near Benghazi showed, however, the loyalist forces' superior armour now stands exposed to devastating aerial attack. Mr Qaddafi is in no immediate danger of losing control of his capital, which houses nearly half Libya's population. But should attacks by the coalition forces continue, the slow whittling away of his heavy weaponry is likely to reduce his options rapidly. As if to emphasise his predicament, Tripoli shook in the early hours of Monday morning as a cruise missile struck and destroyed a building inside the Bab al Aziziya barracks, a sprawling military camp in the city centre used by Mr Qaddafi as his headquarters.

See Saturday's report