TRIPOLI/AJDABIYAH, Libya, April 1 (Reuters) - Moammar Gadhafi's forces intensified their onslaught in the western rebel outpost of Misrata on Friday and his government scorned rebel conditions for a nationwide ceasefire.
A rebel leader, speaking after talks with a U.N. envoy in Benghazi, 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 brought their superior firepower to bear on 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," the spokesman, called Sami, told Reuters by telephone. "We no longer recognise the place. The destruction cannot be described.
"The pro-Gadhafi soldiers who made it inside the city through Tripoli Street are pillaging the place, the shops, even homes, and destroying everything in the process."
Authorities do not allow journalists to report freely from the city.
A doctor in Misrata told Reuters the elite 32nd Brigade had been sent to seize control of the city. "So the question is where is the international community?" he said.
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.
Civilian deaths haunt the calculations of coalition governments. Casualties could shatter a fragile consensus between Western and Arab capitals which first called for the U.N. 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.
"Only those who have large weapons are being allowed through. Civilians without weapons are prohibited," said Ahmed Zaitoun, one of the rebel fighters and part of a brigade of civilian volunteers who have received more training than most.
"Today we have officers coming with us. Before we went alone," he said, and he pointed to a man complaining at being stopped at one of the checkpoints, adding: "He is a young boy and he doesn't have a gun. What will he do up there?"
The new approach has yet to be tested after the rout rebels sustained this week when a two-day rebel advance forward along about 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.
Only two weeks ago, Gadhafi'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 U.S. 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 CIA.
SHOOTING IN TRIPOLI
Heavy gunfire rang out near Gadhafi's fortified compound in Tripoli for about 20 minutes before dawn and residents said they saw snipers on rooftops and heard distant chanting or shouting.
"There were pools of blood on the streets. You will not find anything now. It's been hosed down and cleaned by the fire trucks," said one Tripoli resident.
While Western action has failed to bring any end to fighting or a quick collapse of Gadhafi's administration, signs have emerged of secret contacts between Tripoli and Western capitals.
Foreign minister Moussa Koussa defected in London this week. A Gadhafi appointee also declined to take up his post as U.N. 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 been visiting family members in London, but that 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 prospects for a ceasefire at a news conference after meeting U.N. 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 Moammar Gadhafi and his sons from Libya. This is a demand we will not go back on."
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.
The rebel side was moving quickly to draw income from oil reserves Tripoli says it alone has the right to exploit.
Ali Tarhouni, a top rebel finance official, told a news conference Qatar would provide fuel, medicine, food and other humanitarian needs to rebels as part of a deal eventually to market oil from eastern Libya that remains under a U.N. embargo.
He also said rebels had set up a "quasi-ministry of oil" and oil staff were now working under that body or for the east-based Arabian Gulf Oil Company, which has said it has cut ties with its parent, state-owned National Oil Corp.
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