General Carter Ham, head of the US Africa Command, has expressed skepticism regarding the ability of the Libyan rebels to topple by themselves the regime of Libyan dictator Muammar Gaddafi.

"I would assess that as a low likelihood," General Ham told a Senate hearing, as cited by international media, when asked if he thinks the Libyan opposition rebels could conquer the capital Tripoli and oust Gaddafi.

General Carter Ham as the head of the US Africa Command was in charge of the first phase of UN-mandated Operation Odyssey Dawn, the international air and missile strikes against the Gaddafi regime, before the operation was formally taken over by NATO, after which the US terminated active combat participation in it.

Ham said the bombing raids had damaged the regime's ability to target civilians - except in the besieged city of Misrata. He remarked that the air strikes launched on March 19 had "significantly degraded" the regime's ability "to attack civilians with the notable omission of Misrata."

Ham's skepticism is indicative of growing concern in the USA and Europe that the conflict in Libya is heading towards a stalemate, with the Gaddafi regime retaining control of Tripoli and the rebel irregulars holding on to the Eastern parts of country and Benghazi under the cover of NATO air power.

The rebels remain struggling to defend Misrata; Ham said the regime had stationed armed forces into parts of the city which made it more difficult for NATO to carry out air strikes without killing civilians.