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British warplanes struck a large bunker Friday in Muammar Qaddafi's hometown of Sirte, his largest remaining stronghold, as NATO turned its attention to loyalist forces battling advancing Libyan rebels in the area.

The airstrikes came a day after fierce clashes erupted in the Libyan capital, which remained tense as rebels hunted for the elusive leader and his allies. Pro-Qaddafi forces were shelling the airport and sporadic shooting was reported elsewhere, but the streets of Tripoli were relatively calm on Friday.

The military alliance said NATO warplanes targeted 29 vehicles mounted with weapons near the city, which is 250 miles east of the Libyan capital of Tripoli. Rebels are trying to occupy Sirte but expect fierce resistance from tribesman and townspeople loyal to Qaddafi.

The rebel leadership, apparently trying to avoid the bloodshed that occurred in the battle for Tripoli, has been trying to secure the peaceful surrender of Sirte, but the two main tribes have rejected negotiation efforts.

Qaddafi denied his people basic rights, cracked down harshly on any hint of dissent and squandered the country's vast oil and gas wealth on nations and tribes across sub-Saharan Africa.

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But tribal loyalties are strong in the desert nation of 6 million people. Qaddafi also seeded supporters in key posts and built up militias and armed "revolutionary committees" to be the final line of support for him and his powerful sons if the regular military forces defected.

Qaddafi has tried to rally his followers from hiding, calling on them in an audio appeal as recently as Thursday to fight and kill the rebels.

The two main tribes in Sirte, the Gadhadhfa and the Urfali, remain loyal to the Libyan leader, although many others have disavowed him since the uprising began in mid-February, inspired by a wave of revolutions in Egypt, Tunisia and other Arab countries.

Mohammed al-Rajali, a spokesman for opposition fighters fighting Qaddafi loyalists in the east, said the rebels were trying to reach out to smaller tribes in Sirte but no progress had been made.

"We cannot reach the tribes with which we can negotiate," he told The Associated Press.

But the latest NATO airstrikes on loyalist vehicles defending Sirte appeared aimed at paving the way for the rebel advance if a negotiated settlement proves impossible.

In London, British Defense Secretary Liam Fox said some elements of the Qaddafi regime were in Sirte "where they are still continuing to wage war on the people of Libya." He said NATO would continue to strike at the Qaddafi forces' military capability.

"The regime needs to recognize that the game is up," Fox said.

Maj. Gen. Nick Pope, a British military spokesman, said royal Air Force jets also hit a large headquarters bunker in Sirte with a salvo of air-to-surface missiles.

NATO also bombed surface-to-air missile facilities near Tripoli, a statement said. Officials say Qaddafi's forces are trying to reconstitute their anti-aircraft weapons to pose a threat to humanitarian and civilian flights into Tripoli airport.

The airport was under rebel control but faced regular shelling from pro-Qaddafi forces to the east. At least three planes were burned in heavy shelling overnight, although the airport otherwise appeared largely intact, with a dozen other passenger planes on the tarmac.

"NATO is bombing those guys but they are still shelling from the east of the airport. They have totally destroyed three airplanes but hit others," Nasser Amer, a civil aviation official told the AP.

Amer, a former pilot from Benghazi, traveled to Tripoli on Thursday to try to get the airport running again.

The rebels, meanwhile, were searching for the remnants of pro-Qaddafi forces in buildings in the Abu Salim neighborhood, which saw some of the heaviest fighting on Thursday.

Seven detained men and one woman were sitting in a pickup truck in a rural area between Abu Salim and the airport.

Rebel field commander Sathi Shneibi said there was suspicion that Qaddafi forces were trying to blend in with the civilian population.

"Things are still not stable and we are arresting anybody we find suspicious and taking them to the military council," he said.

Meanwhile, dozens of decomposing bodies were piled up in an abandoned hospital in Tripoli, a grim testament to the chaos roiling the capital as Libyan rebels clash with pro-Qaddafi forces.

The four-story hospital was in the Abu Salim neighborhood, which has seen some of the heaviest fighting this week, although the facility was empty and it could not be determined when the men had been killed. The floors were covered with shattered glass and bloodstains, and medical equipment was strewn about.

One hospital room had 21 bodies lying on gurneys, while 20 others were in the hospital's courtyard next to the parking lot -- all of them darker skinned than most Libyans, covered with blankets. Qaddafi had recruited fighters from sub-Saharan Africa.

With Qaddafi still on the run and vowing to fight to the death, the rebels have struggled to take complete control of the Libya capital after sweeping into the city on Sunday. The fight in Abu Salim has been particularly bloody.

Bursts of gunfire were heard coming from an area near the neighborhood before daybreak Friday. Smoke rose from the area but a rebel at the scene early Friday said the fighting in Abu Salim had ended by nightfall Thursday.

Men believed to be Qaddafi supporters or fighters were left moaning and calling for water at a clinic attached to a fire station in Abu Salim. Curious men from the neighborhood climbed stairs to look at the men, but none offered help.

One of the wounded said he was from Niger and denied any links to Qaddafi. Asked why he was in Libya, he said, "I really don't know." He did not give his name.

Qaddafi had recruited fighters from sub-Saharan Africa, and many others are in Libya as migrant workers. In the turmoil since the rebellion broke out, migrant workers from southern Africa have been harassed.

Associated Press reporters flagged down a cab to take some of the wounded from the clinic to a hospital. The driver at first agreed, but men from the neighborhood intervened, saying the men would have to be interrogated before they could be moved.

The opposition's National Transitional Council, meanwhile, moved forward with efforts to establish political control, announcing it is moving from the country's second-largest city of Benghazi in the east to the Tripoli.

The NTC's finance minister, Ali Tarhouni, said Qaddafi's capture is not a prerequisite for setting up a new administration in the capital.

"We can start rebuilding our country," Tarhouni said late Thursday. "He (Qaddafi) is the one who is basically in the sewer, moving from one sewer to another."