Forces loyal to Libyan leader Muammar Gadafy bombarded the rebel-held city of Misrata with mortars today, and the United States said a fresh ceasefire offer from Gadafy's government was not credible.
The bombardment of Misrata was the heaviest for days and came as Western leaders, gathering for a Group of Eight summit in the French seaside resort of Deauville, were expected to reiterate their determination to force Gadafy out.
Rebel spokesmen in Misrata, scene of some of the fiercest fighting in Libya's three-month-old conflict, said the mortar attack killed three rebels.
Earlier, the sound of exploding mortar shells could be heard every few minutes in the western outskirts of Misrata and there was a steady stream of ambulances, a Reuters reporter said. At Misrata's hospital, rebel fighters mourned their dead colleague.
Suleim Al-Faqih, one of the rebels, said the clashes started when rebels attacked pro-Gadafy forces who were using an excavator to dig a trench to block a road. "We fired on them and advanced. They fell back and started firing mortars," he said.
Spain said it was one of several foreign states contacted by Libyan prime minister Al-Baghdadi Ali Al-Mahmoudi with an offer of an immediate ceasefire.
But White House deputy national security adviser Ben Rhodes, speaking in Deauville at the G8 summit, said the United States did not see the new Libyan ceasefire offer as credible because it was not accompanied by action.
Libya was not complying with UN demands and its forces were still attacking population centres, so the United States would continue with the military campaign, he told reporters.
At a news conference in Tripoli, Mr Mahmoudi said the offer was based on an existing African Union "roadmap" to resolve the conflict, which does not include any mention of Col Gadafy's own future - a crucial sticking point.
"Libya is serious about a ceasefire," he said. "The leader Muammar Gadafy is the leader of the Libyan people; he decides what the Libyan people think. He is in the hearts of the Libyan people. If he departs, then so do all the Libyan people."
The rebels said they wanted any government initiative to include the Libyan leader's departure as a first step. "We welcome any initiative which starts with the departure of Gadafy, his sons and his regime from Libya," Mustafa Abdel Jalil, head of the rebel Transitional National Council, said on Al Jazeera television. "Any initiative that contains this point as a first step, we welcome it," he said.
Col Gadafy's security forces cracked down ferociously when thousands of Libyans rebelled against his rule. Nato missiles and warplanes have been bombing targets in Libya for two months under a UN mandate to protect civilians from attack.
Rebels now control the east of the country, around their main stronghold of Benghazi, and pockets of land in the West.
But the conflict has reached stalemate on the ground, with the rebels unable to advance towards Tripoli and Nato powers - wary of getting sucked into new conflicts after their experience in Iraq and Afghanistan - refusing to put troops on the ground.
Nevertheless, Western officials say they are confident that they are gradually loosening Col Gadafy's grip on power through a combination of sanctions and military and diplomatic pressure.
"You are wearing down a regime over time," said a US defence official. "You make the elites feel uncomfortable; you get dissension in the upper ranks. It doesn't happen quickly. What you are trying to do is get the regime to read the writing on the wall."
Britain's defence ministry said its Typhoon and Tornado aircraft had used Paveway guided bombs to attack a military vehicle depot at Tiji, in western Libya, which was being used to support attacks on the rebel-held Western mountains region.
Col Gadafy denies his troops target civilians and says his security forces were forced to act to put down a rebellion by criminals and members of al-Qaeda.
Anxious to break the stalemate, some Western powers are pressing for Nato to intensify its operations. France has said it will deploy attack helicopters, which are better able to pick out targets on the ground than high-altitude aircraft.
British prime minister David Cameron, after talks with French president Nicolas Sarkozy, said Britain was considering the deployment of its own attack helicopters. "We are looking at ways to turn up the pressure (on Gadafy), including helicopters. When we are ready to make an announcement we'll make an announcement," he said.
Mr Sarkozy, the most hawkish Western leader on Libya, is hosting the G8 summit and is expected to use it to press other powers to ramp up military and diplomatic pressure.
Attempts to build a consensus at the summit on Libya may be prevented by Russia, which opposes the Nato bombing.
In Moscow, a foreign ministry spokesman said the use of Nato helicopters in Libya would go beyond the United Nations resolution which mandated intervention to protect civilians. "The delivery of such kinds of weapons raises the most serious fears," spokesman Alexander Lukashevich was quoted as saying by Russian news agencies.
Reuters