Tripoli/Washington: Setting the stage for a battle that may help decide the war in Libya, the US and European warplanes pounded Muammar Gaddafi’s tribal homeland of Sirte with rebels reported to be at its doorstep.

A series of explosions were heard in the city on Monday which triggered a mass exodus from the Gaddafi's hometown, which he has turned into a well fortified garrison.

Unconfirmed reports said the rebel forces had routed pro-Gaddafi defenders and opposition spokesman Shamsi Abdul Molah told a news channel that the rebels had moved into the city on Sunday night.

The French air force used 20 jets backed by AWACS surveillance plane to down five Gaddafi fighters and two Mi-35 helicopter gunships and British warplanes destroyed three armoured vehicles.

The rapid advance westwards of the rebels comes as top Obama administration officials including Defence Secretary Robert Gates and Secretary of State Hillary Clinton said they have received hints that key aides of Gaddafi may be ready to abandon him.

"The battle of Sirte may be the undoing of Gaddafi," a newspaper reported quoting US officials.

Though the Western coalition officials believe that an ultimate showdown could be at Sirte, the rebel commanders expect a major battle in the area around Tripoli as opposed to Sirte.

As western warplanes and missiles renewed their bombings of military sites in and around Tripoli, NATO agreed at a meeting in Brussels to take over the command of the 'Operation Odyssey Dawn'.