A day after glimpsing victory in Misrata, Libyan rebels came under a renewed barrage of heavy shelling from retreating government forces.
Pro-Gaddafi forces pounded the besieged city with rockets despite the government's claims that its troops were withdrawing to give the local tribes time to deal with the rebels, either through dialogue or more force.
The prospect of a return to the stalemate in the rebel-held city prompted US senators yesterday to call on Washington to step up its military response in Libya to bring a rapid end to a conflict that many fear could bog down the West indefinitely.
Misrata, a key staging post on the road to the capital Tripoli, is the only remaining rebel-held city in western Libya and has been ravaged by intense urban warfare in the past two months that has left hundreds dead. As government forces kept up a sustained artillery assault on Misrata yesterday, the lightly-armed rebels claimed they had driven out troops from the main hospital, where they had holed up, to the edge of the city, the Associated Press reported.
That development comes just days after rebels celebrated a key victory when they routed snipers from a building on the city's main street.
On Friday, Libya's deputy foreign minister, Khaled Kaim, said soldiers were pulling back to leave the local tribes to deal with the rebels with a Monday deadline. As the shelling continued, he clarified early yesterday that they had not withdrawn but had merely "suspended" operations.
Western officials and rebels were sceptical that pro-Gaddafi forces would leave it to the tribes. "This may be cover for using more insurgent-type warfare without any uniforms and without tanks," British Foreign Secretary William Hague told the BBC.
At least 25 people are thought to have died in fighting on Saturday, one of the bloodiest days yet, with at least one more killed yesterday. Even with Nato strikes against the regime that began last month, fighting between the rebels and Gaddafi's troops has largely reached a stalemate. In the East, rebels are engaged in a back-and-forth west of the rebel capital, Benghazi.
US senators called on Washington over the weekend to step up the military pressure on Libya, with some calling for direct strikes at Colonel Gaddafi and his inner circle.
"My recommendation to Nato and the administration is to cut the head of the snake off, go to Tripoli, start bombing Gaddafi's inner circle, their compounds, their military headquarters in Tripoli," Republican Senator Lindsey Graham told CNN's State of the Union. Senator John McCain, who has just returned from a trip to Benghazi, also supported bringing more pressure to bear on the Libyan regime, but warned that targeting dictators "is a little harder than you think".
"It's pretty obvious to me that the US has got to play a greater role on the air-power side," he told NBC's Meet the Press. "Our Nato allies neither have the assets, nor, frankly, the will."
Washington said last week it was deploying the controversial unmanned aerial drones in Libya, a move that suggested the US is willing to assume a larger role in the alliance to enforce the UN resolution.