NATO yesterday threw its weight behind growing calls for Muammar Gaddafi to quit, as rebels fighting to topple the veteran Libyan strongman reported an intensive blitz by alliance warplanes and as loud blasts were heard in Tripoli.

The port area of Libya’s besieged third city Misrata came under heavy attack by Col Gaddafi’s forces, who fired dozens of Grad missiles and tank shells that killed at least 13 people and wounded 50, a rebel spokesman said.

The key crossroads town of Ajdabiya on the front line between the rebel-held east and the mainly government-held west, recaptured from loyalist forces at the weekend, came under renewed assault, an AFP correspondent reported.

In Cairo, UN chief Ban Ki-moon called for a “political” solution and immediate ceasefire, at an international conference hosted by the Arab League.

European Union foreign policy chief Catherine Ashton, who also attended the Cairo conference, appealed to Col Gaddafi to resign with immediate effect.

And a Nato declaration said “we welcome the outcome of the first meeting of the contact group which took place yesterday (Wednesday) in (the Qatari capital) Doha and strongly endorse its call for Gaddafi to leave power.”

Alliance foreign ministers played down any rift after France and Britain pressed allies to contribute more combat jets to the mission and intensify the raids against regime tanks and artillery shelling civilians.

“We are also sharing the same goal which is to see the end of the Gaddafi regime in Libya. And we are contributing in many ways in order to see that goal realised,” said US Secretary of State Hillary Clinton.

She later told Nato allies: “For our part, the US is committed to our shared mission. We will strongly support the coalition until our work is completed.”

German Foreign Minister Guido Westerwelle, whose country shocked allies by refusing to back the UN resolution authorising the military operation, said Nato supports the aspirations of the Libyan people.

“We are united by the common goal, that we want a free and democratic Libya. The dictator Gaddafi, who started a civil war against his own people, must go,” Mr Westerwelle said at the start of the two-day meeting in Berlin.

But differences remained over the air raids against forces threatening the population, which are being conducted by just six of the 28 allies. Rebels have urged Nato to step up the air campaign as the mission has failed to shift the balance of power so far.

Nato Secretary General Anders Fogh Rasmussen said Wednesday’s meeting in Qatar of the international contact group on Libya, which promised the rebels cash and the means to defend themselves, “laid out a good foundation”.

“We will now discuss how we can continue the military operation leading to a successful result,” he said.

Military action was first launched by Britain, France and the United States on March 19, but Nato took over the operation two weeks ago after overcoming French reservations about letting the Western military organisation alliance lead it.

The Berlin meeting came as Nato planes put on a show of force on the Libyan front line, with rebels reporting they were bombing targets on the road leading west, towards the key oil refinery town of Brega on the central Mediterranean coast.

An AFP correspondent heard loud explosions just west of the town of Ajdabiya, where deadly exchanges raged on Saturday and Sunday killing dozens of loyalist troops and an undisclosed number of rebel fighters.

There was no immediate confirmation from Nato that warplanes under its command were engaged.

Loud explosions rocked the capital Tripoli close to Col Gaddafi’s residence in the Bab al-Aziziya neighbourhood, AFP correspondents reported.

Warplanes were heard swooping at low altitude over the city centre near the hotel where most foreign journalists are based and veteran leader Col Gaddafi has his residence.

Large explosions struck around 3 p.m. followed by anti-aircraft fire and two more loud blasts less than an hour later.

A Western official speaking to AFP on condition of anonymity said French, British and Italian military attaches were now in the rebel stronghold of Benghazi and they were providing indirect information about the situation at the front line to Nato.

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