Troops loyal to Muammar Gaddafi have launched counter-offensives against towns held by protesters, increasing fears that Libya is heading for a civil war rather than the swift revolutions seen in Tunisia and Egypt.
An air strike Monday targeted protesters east of the oil town Ras Lanuf, where fighters opened fire with anti-aircraft guns following an explosion, an AFP reporter said.
The reporter at a checkpoint on the eastern outskirts of Ras Lanuf saw an explosion and a big cloud of smoke on the horizon, about two kilometers (one mile) east of the town in the desert.
All six anti-aircraft guns at the checkpoint then opened a barrage of fire into the sky. Rebels then started jumping up and chanting.
The resilience of Gaddafi's forces in the face of the insurrection which started in mid-February and their ability to counter-attack has raised the prospect that this oil exporting nation is heading for protracted conflict.
But after what residents said was fierce fighting on Sunday with artillery, rockets and mortar bombs, protesters announced they had fought off Gaddafi's forces in the towns of Zawiyah, to the immediate west of Tripoli, and Misrata to the east.
Residents of the eastern Libyan oil town of Ras Lanuf, held by protesters, however, fearing assault by government forces, were leaving in cars laden with belongings on Monday and rebels said they had moved weapons into the desert for safekeeping.
At least seven people were killed and more than 50 wounded in clashes at the coastal hamlet of Bin Jawad, hospital figures showed Monday.
The casualty list posted at Ajdabiya hospital, where most of the wounded were taken after Sunday's clashes, reported seven dead and about 52 people hurt.
"Indiscriminate" attacks on civilians
Gaddafi's forces were holding off protesters near the Libyan leader's hometown and recaptured a key city, as the United Nations prepared to send a special envoy to Tripoli while its chief demanded an end to "indiscriminate" attacks against civilians in Libya and warned Tripoli that anyone who violates international law will be brought to justice.
Untold numbers of "injured and dying" in the western city of Misrata prompted a U.N. demand for urgent access to the civilian population repeatedly shelled by Gaddafi tanks Sunday.
The U.N. Secretary General, meanwhile, demanded an end to "indiscriminate" attacks against civilians in Libya and warned Tripoli that anyone who violates international law will be brought to justice.
Ban Ki-moon's press office said Gaddafi's foreign minister agreed to let a "humanitarian assessment" team visit Tripoli and he named a special envoy to deal with the regime, former Jordanian foreign minister Abdelilah al-Khatib to undertake "urgent consultations" with the Tripoli government.
"He (Ban) notes that civilians are bearing the brunt of the violence, and calls for an immediate halt to the government's disproportionate use of force and indiscriminate attacks on civilian targets," the statement said.
"He stresses that those who violate international humanitarian law or commit grave crimes must be held accountable," it added.
Ban appealed to the Libyan government to call an end to the hostilities and urged it to comply fully with a U.N. Security Council sanctions resolution adopted a week ago.
That resolution called for an end to the violence and imposed U.N. sanctions on Qaddafi, his family and inner circle. It also referred the violent crackdown against anti-government demonstrators to the International Criminal Court.
Protesters' frustration was apparent as ragtag opposition forces squabbled over a bitter defeat in Bin Jawad.
And revolutionary leaders rejected a secret British mission sent to establish contact with them. In the eastern city of Benghazi, a protesters stronghold, a spokesman said the British team that landed nearby had not made prior arrangements, and was sent away.
Pro-Gaddafi forces beat back protesters making a westward approach to Gaddafi's hometown of Sirte.
"We retreated from Bin Jawad. Ras Lanuf will be our line of defense," rebel Aqil al-Fars told AFP.
Demonstrators in the oil port of Ras Lanuf argued about what went wrong in nearby Bin Jawad, with one proclaiming: "The problem is we have no leadership."
Attacks in the western city of Misrata prompted the U.N. demand for urgent access to civilians.
"People are injured and dying and need help immediately," said U.N. emergency relief coordinator Valerie Amos. "I call on the authorities to provide access without delay to allow aid workers to help save lives."
Residents of Misrata, strategically located between the capital Tripoli and Sirte, said earlier that government tanks were shelling the town and warned of "carnage" if the international community did not intervene.
A spokesman for the protesters confirmed Misrata was under intense fire from pro-Gaddafi forces and reported casualties, but insisted the city was still in rebel hands.
The opposition vehemently denied a report by Allibiya state television that Gaddafi's forces had retaken a string of strategic oil towns from the rebels.
Taking back control
Thousands celebrated in Tripoli with gunfire, horn-honking and flag waving after Allibiya said government forces had taken control of Misrata, Libya's third city, the key oil hub of Ras Lanuf and even Tobruk near the Egyptian border.
AFP reporters in Ras Lanuf, taken by protesters early on Saturday, confirmed it was still in opposition hands despite being hit by air strikes early Sunday.
A defected officer, Colonel Bashir al-Moghrabi, told reporters the opposition also still controlled Zawiyah, west of Tripoli, where fierce battles took place on Saturday.
A local doctor said there had been a "massacre" in Zawiyah and a Sky News journalist said Gaddafi's forces had fired on civilians.
Libya's deputy foreign minister Khaled Kaaim told reporters the armed forces would not take the fight to the protesters.
"The order for the armed forces is to take defensive positions, and not to engage the enemy except if they go on the offensive," he said.
Ali Errishi, Gaddafi's former immigration minister who joined the revolt, voiced growing frustration at a lack of international assistance for the ill-equipped force.
He told CNN the United States had missed an opportunity to oust the Libyan strongman by "dragging their feet" over aiding the protesters in the early days of the uprising, now approaching its fourth week.
"We asked, we don't want a no-fly zone actually, we just want air cover," Errishi said.
A former U.S. envoy to the United Nations, Bill Richardson, said it was time to "covertly arm the rebels" and enforce a no-fly zone over the north African country, to prevent Gaddafi using his air power against his own people.
British team sent home
Britain was forced to admit its own, secret, attempt to begin negotiations with the rebels had ended ignominiously after opposition forces arrested a diplomat and a protection squad inserted clandestinely by helicopter.
"The team went to Libya to initiate contacts with the opposition. They experienced difficulties, which have now been satisfactorily resolved," said Foreign Secretary William Hague after the men were sent home by opposition leaders.
Britain's Sunday Times said the eight-man group comprised a diplomat and SAS (Special Air Service) soldiers, who the BBC said were dressed in black.
"We do not know the nature of their mission. We refused to discuss anything with them due to the way they entered the country," said spokesman Abdul Hafiz Ghoqa.
U.S. talk of a no-fly zone cooled last week after a top commander said air strikes would first have to take out ground defenses, but President Barack Obama said all options remain on the table.
French Foreign Minister Alain Juppe reiterated the prevailing European and U.S. view that military intervention in Libya would have "absolutely negative" effects.
But he said a no-fly zone would be a possibility should the fighting "become bloodier."
Wounded people streaming back from Bin Jawad to Ras Lanuf said Gaddafi loyalists lured them into a trap, hiding in homes, mingling with civilians and hunkering down on rooftops before opening fire on convoys of volunteers.
In an apparent counter-claim, state television later cited the military as saying the rebels were holding "human shields" in residential sectors of some cities.
Two attacks by lone warplanes targeted a checkpoint on the eastern edge of Ras Lanuf and a rebel camp in a former military barracks in the center Sunday.
Elsewhere Sunday, Yemen's opposition movement vowed to intensify protests against the regime of President Ali Abdullah Saleh, after the embattled leader refused to resign by the end of the year.