US and allied forces on Thursday shifted focus on hitting Libyan ground forces, targeting tanks and artillery to obliterate Muammar Gaddafi's war waging machine. The shift to attack the ground forces came after coalition commanders claimed that Libyan air force had been completely destroyed and that the US and NATO warplanes had total sway of the Libyan sky. As the allied operation entered the sixth day, the French Foreign Minister Alain Juppe warned that the campaign may go on for weeks. He was speaking to reporters in Brussels ahead of a crucial EU-NATO meeting to discuss how to coordinate airstrikes on Libya. The coalition warplanes pounded the rebel-held city of Misrata, forcing Gaddafi's forces to pull back from the outskirts of the city, but residents said by nightfall the tanks and artillery had renewed their the shelling on the city which is virtually under siege. Similar strikes were aimed at Gaddafi's forces stalking the towns of Adjabiyah and Zintan. The allied forces also continued Tomahawk missile strikes and air bombing of the Libyan capital Tripoli. The BBC correspondent said the city was rocked by seven explosions and witnesses said a military base at Tajura, 32 kms east of the capital was hit. Al Jazeera said eight explosions were also heard in the east of the capital last night. The official JANA news agency said coalition raids on Tajura had killed a large number of civilians. JANA news agency claimed that the latest raid had targeted rescue workers who were trying to remove the dead and wounded from the rubble left by the first two raids.