BENGHAZI, Libya -- Muammar al-Qaddafi's forces rocketed rebel fighters Thursday in the formidable strongholds and training camps they have built up in the strategic mountain heights southwest of the Libyan capital, rebels said.
The two sides appeared to be fighting for control of the two highways to the north and south of the Nafusa mountain range, which slices across the desert south of Tripoli to the western border with Tunisia. Rebels, in particular, have used the road, bringing in supplies for camps to train fighters for what they hope will be a future push on the capital.
NATO airstrikes resumed in Tripoli overnight. A Libyan government official said six sea vessels docked in the city's port were hit -- five coast guard boats and a warship. Flames and smoke could be seen rising from one of the vessels.
The shuddering airstrikes could be heard as Libyan government spokesman Moussa Ibrahim spoke to reporters at a late-night news conference. He said that in a meeting Tuesday with Russian leaders, an envoy offered to withdraw Libyan fighters from cities if rebels do the same, as part of a peace deal.
"We are even prepared to go as far as withdrawing our army from all Libyan cites and population centers," he said. "This is a new offer."
Ibrahim said the offer was the furthest the government had gone since fighting broke out against the rebels. He said as part of the deal, NATO would also have to halt its strikes of Libyan targets.
There was no immediate comment by rebel leaders based in the eastern city of Benghazi.
The rebels have rejected previous offers, emboldened by NATO strikes that have helped them cling to swaths of the country, and because they say they don't trust Qaddafi's regime.
Government officials said early Friday that the overnight NATO strikes targeted six vessels in Tripoli's sea port -- a crucial lifeline for the government-held parts of the country because there is a no-fly zone in place over Libya.
Five of the vessels were coast guard boats, said Mohammed Rashid, general manager of the Tripoli port. The six was a warship docked for repairs in the port, he said.
Rashid said the coast guard boats were used to patrol Libyan waters for immigrant boats trying to make it to Europe, to prevent polluting activities and search-and-rescue activities.
The port official said some damage was done to the port, but that it was minimal. A government official later said they feared that ships would shy away from the Tripoli port after the NATO strikes, driving up the cost of basic goods that arrive by sea, and insurance costs.
In a tour given to reporters at a distance from the area, a warship could be seen on fire. Large, licking flames and plumes of black smoke could be seen rising from the ship.
AP television footage showed the strikes hitting the area. There was a loud boom and then a flash of orange and red as explosives detonated. It appeared that some five strikes targeted the area. Afterward, gunfire and anti-aircraft fire could be heard crackling around Tripoli.
Another strike early Friday targeted a police academy in the Tripoli neighborhood of Tajoura, a government official said.
Also on Thursday, Qaddafi appeared briefly on Libyan state TV, his first appearance in several days.
As the fighting in the mountains intensified this week, the rebel leadership in the east of the country said Thursday it was receiving graphic reports of hospitals overwhelmed with casualties and of wounded having to be loaded onto donkeys and smuggled past government blockades to get treatment elsewhere.
The situation in the Nafusa mountains "remains dire, really dire," said Jalal al-Gallal, a spokesman for the rebel governing council, based in the eastern city of Benghazi.
The mountain range has been one of the few zones of opposition in western Libya since the early days of the uprising against Qaddafi's four-decade rule in mid-February. Most of the rebel forces are concentrated in the east.
The long highways on either side of the mountain range are key to both sides. The government needs easy passage without harassment from the ridgeline above if it wants to keep control of a huge swath of the west.
The rebels run supplies from the border. Also, they have used the passageway to smuggle back fighters who had fled battles in other parts of the country and ended up in Tunisia, said Omar Hussein, a spokesman for the Nafusa mountain rebels.
Their position on the roads from the mountains to the former rebel stronghold of Zawiya on the north coast and Tripoli beyond made them a target, he said.
"Qaddafi knows that the rebels' plan is to come down from the mountains, then head to Zawiya, and from there to Tripoli. He is trying to delay this march," Hussein said.
Much of Thursday's fighting focused on the city of Zintan, the rebel command center for the mountain range. Rebels fought to hold back government troops rocketing their positions to the east and southeast of Zintan, said resident and activist Hamed Enbayah. The shelling killed at least one rebel fighter and wounded three others, he said.
NATO airstrikes in Libya's embattled western mountains are having no noticeable effect, a rebel representative from Zintan told reporters Thursday.
"We were there for three days, and Qaddafi forces never stopped shelling" Zintan, Ahmed Bin-Moussa told a news conference the day he arrived in the rebel bastion of Benghazi.
Points along the entire mountain range have been under intensified attack since early this week. Residents of some areas said the fighting had trapped them inside their homes and cut off food and medical supplies.
Britain's defense secretary, Liam Fox, told lawmakers on Thursday that U.K. fighter jets have fired at least 240 missiles in about 440 sorties over Libya since NATO's campaign of airstrikes began. Fox outlined the figures in a written statement and said they were accurate up to May 8.