TRIPOLI/AJDABIYAH, Libya - Muammar Gadhafi's government scorned rebel conditions for a nationwide ceasefire, and there was no sign of international diplomatic efforts cooling the Libyan conflict.

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Western-led forces bombarded "civilian and military locations" late on Friday in the towns of Khoms, about 100 km (60 miles) east of Tripoli, and Arrujban, about 190 km to the southwest, state-controlled Libyan television said.

A rebel leader, speaking after talks with a UN envoy in Benghazi, earlier on Friday offered a truce on condition that Gadhafi left Libya and his forces quit cities now under government control.

"They are asking us to withdraw from our own cities .... If this is not mad then I don't know what this is. We will not leave our cities," government spokesman Mussa Ibrahim told reporters in Tripoli a few hours later.

Rebels speaking from Misrata said Gadhafi's forces had intensified their siege of the insurgents' last western enclave with an intense bombardment that was killing and maiming civilians.

"They used tanks, rocket-propelled grenades, mortar rounds and other projectiles to hit the city today. It was random and very intense bombardment," a spokesman called Sami told Reuters by telephone. "We no longer recognise the place. The destruction cannot be described."

Authorities do not allow journalists to report freely from the city.

Gadhafi's government in turn accused Western leaders of a "crime against humanity", saying allied warplanes had killed at least six civilians in a new attack. "Some mad and criminal prime ministers and presidents of Europe are leading a crusade against an Arab Muslim nation," Ibrahim said.

Rebels try to strengthen discipline

Civilian deaths haunt the calculations of coalition governments. Casualties could shatter a fragile consensus between Western and Arab capitals which first called for the UN mandate to create a no-fly zone and protect civilians.

Libyan rebels moved heavier weaponry towards government forces at Brega on Friday and sought to marshal their ragtag units into a more disciplined force to fend off Gadhafi's regular army and turn the tide of recent events.

Rebels said neither side could claim control of Brega, one of a string of oil towns along the Mediterranean coast that have been taken and retaken by each side in recent weeks. Warplanes flew over Brega, followed by the sound of explosions.

Rebels said more trained officers were at the front, heavier rockets were seen moving from the eastern rebel stronghold of Benghazi towards Ajdabiyah to the south late on Thursday and checkpoints were screening those going through.

The new approach has yet to be tested after the rout rebels sustained this week when a two-day rebel advance along about 200 km (125 miles) of coast west from Brega was repulsed and turned into a rapid retreat over the following two days.

On the road between Ajdabiyah and Benghazi were newly-dug rebel gun emplacements.

Two weeks ago, Gaddafi's forces were at the gates of Benghazi and the Libyan leader pledged "No mercy, no pity" for rebels who would be flushed out "house by house, room by room".

A US think tank said the military chief of the rebels, Khalifa Hefta, is a veteran Arab nationalist guerrilla foe of Gadhafi who had backing in the past from the US Central Intelligence Agency.

While Western action has failed to bring any end to fighting or a quick collapse of Gadhafi's administration, signs have emerged of contacts between Tripoli and Western capitals.

Foreign minister Moussa Koussa defected in London this week and a Gadhafi appointee declined to take up his post as UN ambassador, condemning the "spilling of blood" in Libya. Other reports of defections are unconfirmed.

A British government source said Mohammed Ismail, an aide to Gadhafi's son Saif al-Islam, had visited family members in London, and  Britain had "taken the opportunity to send some very strong messages about the Gadhafi regime".

Rebel oil exports

Rebel National Council head Mustafa Abdel Jalil discussed how a truce might be achieved, after meeting UN special envoy Abdelilah al-Khatibset in Benghazi:

"We have no objection to a ceasefire but on condition that Libyans in western cities have full freedom in expressing their views... Our main demand is the departure of Muammar Gadhafi and his sons from Libya. This is a demand we will not go back on."

But there appeared to be confusion over a truce even within rebel ranks. "We do not agree to the ceasefire. We are defending ourselves and our revolution," said rebel spokesman Hafiz Ghoga.