Libyan leader Muammar Gadhafi shakes hands with a man as he travels in a convoy through the streets of Tripoli in this still image taken from video April 14, 2011. Libyan state television on Thursday broadcast footage of Gadhafi driving around Tripoli in an open-top vehicle and said he went on the outing while the Libyan capital was being bombed by NATO. Wearing a green safari hat, dark glasses and a black jacket, Gadhafi pumped his fists in the air and waved as pedestrians chased his convoy of SUVs through the streets. [Photo/Agencies]

Libyan leader Muammar Gadhafi raises his arms as he travels in a convoy through the streets of Tripoli in this still image taken from video April 14, 2011. [Photo/Agencies]

TRIPOLI - Libyan leader Muammar Gadhafi rolled defiantly through the streets of Tripoli, pumping his fists as he poked through the sun roof of an SUV on Thursday _ the same day that NATO airstrikes shook the city. The alliance's foreign ministers, while united in their aim to pressure the Libyan leader to go, argued at a meeting over whether to step up military operations that have so far failed to rout him.

Gadhafi gave no sign that he's willing to relent, despite two months of civil war and mounting international pressure for him to move aside. Instead, his loyalists pounded rebel positions in the besieged western city of Misrata with dozens of rockets for several hours, killing at least 13 people.

The main target of the assault was Misrata's port, the only lifeline for rebels who have been trying to defend positions in the city, Libya's third-largest, against Gadhafi's forces.

Early Friday, Gadhafi's daughter Aisha sent another defiant message from her father's Bab al-Aziziyah compound in the capital of Tripoli, badly damaged exactly 25 years ago, in an April 15, 1986 bombing by US warplanes. That attack came in response to a bombing that had killed two US servicemen at a German disco.

"Leave our skies with your bombs," Gadhafi's daughter told a cheering crowd, addressing the international community. "We are a people that cannot be defeated."

Wearing a green headscarf and a leather jacket, she waved to the crowd of several hundred and led them in chants from a second-floor balcony that in the past was used by her father to deliver speeches.

On Thursday, several large explosions were heard in Tripoli and a column of black smoke rose from the southeastern part of the city, followed by the sound of anti-aircraft guns, a resident said.

Libyan state television showed Gadhafi _ dressed in a black Western blazer, black crew neck T-shirt, sunglasses and a hat _ standing through the open sun roof of a sport utility vehicle on a fist-pumping, rapid ride through Tripoli with dozens of supporters chasing behind him. Libyan TV said the trip came on the same day that NATO airstrikes hit military and civilian areas in the capital.

The TV report said there were civilian casualties from the attacks. The report could not be confirmed.

The fighting in Libya began in mid-February when large anti-government protests escalated into a civil war. Rebels hold much of eastern Libya, while Gadhafi controls the west, with the front line shifting back and forth in the middle. Three weeks of international airstrikes haven't routed Gadhafi's forces.

Gadhafi's troops unleashed three hours of heavy shelling on the port city of Misrata, which is partly held by rebels. The port is Misrata's only lifeline, and government forces fired tank shells and dozens of Grad missiles, according to witnesses who spoke on condition of anonymity because they feared retaliation.

"They want to flatten the area to deploy the troops on foot and invade the city," said one of the witnesses, a doctor whose first name was Ayman. He added that a ship sent by Doctors Without Borders to evacuate 165 critically injured people to Tunisia had been scheduled to arrive Thursday morning at Misrata's port, and he believed the government had shelled the port to interfere with the humanitarian aid.

Another doctor in Misrata, who gave his name only as Khaled for fear of retribution, said some of those killed were inside their houses asleep at the time of the shelling. Among the dead were two men aged 75 and 80.

Gadhafi forces have control of a highway on the outskirts of Misrata, Libya's third-largest city.

UN Secretary-General Ban Ki-moon chaired a Cairo meeting of regional and international organizations on Libya and set three targets: reaching and implementing a cease-fire, delivering humanitarian aid and starting a dialogue on Libya's future.

"Shelling your own people is not acceptable," he said at a meeting at Arab League headquarters, referring to actions by Gadhafi's forces. "This is a violation of human rights."

At a two-day meeting of NATO foreign ministers in Berlin, the United States and its allies put up a united front on the goals of the alliance's stalemated military mission in Libya but failed to resolve behind-the-scenes squabbling over how to achieve them.

NATO members agreed on paper with President Barack Obama that Gadhafi had to go to end the crisis, they also made clear that they would not be the ones to oust him. Although several NATO members want the alliance to commit more planes to expand the air campaign, the first day of meetings closed without any specific commitments for more aircraft.

US Secretary of State Hillary Rodham Clinton appealed for unity, saying Gadhafi was taunting the alliance by continuing to strike cities held by rebels seeking his overthrow.

"As our mission continues, maintaining our resolve and unity only grows more important," Clinton said. "Gadhafi is testing our determination."

The United States is resisting suggestions that it resume a large combat role to break a deadlock between rebels and better-armed forces loyal to Gadhafi.

Clinton and other top diplomats pointedly said their U.N. mandate for an air campaign does not extend to Gadhafi's exit by force.

The allies again resolved to enforce a U.N. arms embargo, protect civilians acting to push Gadhafi forces out of cities they have entered, and get in humanitarian aid.

But differences over the scope of the military operation persisted, with Britain and France insisting on more action, particularly from sophisticated US surveillance and weapons systems, and U.S officials maintaining that the alliance already has the tools to get the job done.

French Foreign Minister Alain Juppe said Paris "had wanted (NATO) to intensify its strikes, and we received the assurance that that would be the case."

Clinton did not say if the US would send more ground attack craft, but she said Washington would continue to support the NATO mission until its goals were met.

Rebel spokesman Mustafa Gheriani said the opposition in Benghazi is encouraged by the diplomatic talks but worried that it won't translate in to concrete action fast enough to prevent more civilian deaths.

"It will be interesting to see if there is any movement on the ground or just a lot of talk and no action," he said. "Is there something else on the diplomatic ground that they know that we don't to put more pressure on Gadhafi? The guy is still shelling and killing, and it makes no difference to him."

He mentioned specifically the shelling of Misrata and said the international community's actions will largely determine how long the conflict lasts.

"They wrote off Gadhafi's regime. The question is how fast their plan is going to take care of him. We know arming ourselves will lead to the eventual toppling of the regime. But are we willing to wait two years or three years or a year and a half? How many victims do we have to accept?"

Rebel leaders have said they would only consider a truce if it Gadhafi is removed from power first.

At the Cairo meeting of top diplomats, European Union foreign policy chief Catherine Ashton said Gadhafi "must leave immediately" and that Libyans should be given a chance to choose a new leader.

Arab League chief Amr Moussa told reporters after the meeting that the situation in Libya is "very grave."

Brief clashes erupted between pro- and anti-Gadhafi demonstrators outside the meeting. The two camps hurled rocks at each other, with at least one protester seen with blooded face after being hit in the head with a stone. The anti-Gadhafi protesters outnumbered the pro-Gadhafi demonstrators, chased them and forced them to flee.

NATO said it had conducted 153 sorties in the last 24 hours, striking 13 bunkers, one tank and one armored personnel carrier in the Tripoli area and three multiple rocket launchers in the Brega area.

Journalists were taken to Tripoli's Fateh University where they were shown damage they were told was the result of an airstrike earlier in the day. The blast shattered windows of several buildings, including two student cafeterias, and glass shards were scattered across the floor. Tiles of false ceilings had been knocked out in several lecture halls.

Government minders traveling with the journalists said the strike had hit a military target nearby and white smoke was seen rising from a group of trees several hundred yards from the campus. The minders would not elaborate or allow anyone to approach the targeted area. However, one journalist who had snatched a glimpse from a rooftop said she had seen an anti-aircraft battery at the site. Photographs taken later showed a large military truck in the area.

A Tripoli resident said many people were fasting in preparation for mass anti-Gadhafi protests Friday, the 25th anniversary of the 1986 US raid on Tripoli.

Life in Libya "is becoming harsh," with prices skyrocketing, gasoline scarce and long lines in front of bakeries, said the resident, speaking on condition of anonymity for fear of retribution.

Al-Sadek al-Ghariani, a top Muslim cleric in Libya, said in a video posted on Facebook that it was a religious duty to join Friday's protests. In February, he issued two fatwas calling for anti-Gadhafi protests and then went into hiding. Gadhafi forces apparently are trying to find him.

At the western edge of Ajdabiya, the main gateway town into the opposition-held east, two wounded rebel fighters were brought through, and the rebel forces retaliated by firing rockets in the direction of Brega.

In western Libya, rebels attacked a small military base about 60 kilometers (37 miles) from Nalut and chased away 40 soldiers who had been trying to stop aid from Tunisia and harassing people trying to flee into that country. In apparent retaliation, Libyan government forces shelled the town of Tikut.

Rebel chief of Staff Abdel-Fatah Younes said the opposition fighters have received new anti-tank weapons from Qatar and that experts from that country are training the forces to use them.

Also Thursday, Libyan TV reported Gadhafi's son, Seif al-Islam Gadhafi, mediated the release of Arab broadcaster Al-Jazeera correspondent Amar al-Hamdan, who was en route to the Libya-Tunisian border.