Libyan rebels have regained control of the strategic oil town of Ajdabiya and Brega after week-long air strikes by western coalition crippled Muammar Gaddafi's forces. Rebels told AFP that Gaddafi's forces have retreated to Al-Bisher, 30 Km west of Brega. Libyan government officials said that the army has withdrawn from Ajdabiya to save residents from more bloodshed. In Misrata, forces loyal to Gaddafi shelled an area on the outskirts of the city. The port city has experienced some of the heaviest fighting between rebels and forces loyal to Gaddafi since the uprising began on February 16. In a bid to force Gaddafi to quit, the coalition has stepped up air raids on his tanks and artillery outside Ajdabiya. British RAF Tornado aircraft have been firing Brimstone guided missiles at Gaddafi's forces massed around Ajdabiya, a town seen as the gateway to Benghazi and the oil town of Tobruk. Large explosions were also heard in the Libyan capital Tripoli yesterday. Witnesses said, a military radar site was set on fire in that city's suburb of Tajura. Meanwhile, US President Barack Obama has said the military mission in Libya is clear, focused and limited. Obama once again ruled out sending any American ground forces to the North African country and sought to project the campaign in Libya as a completely multi-lateral mission.