NATO has promised "all necessary resources" to Libya's opposition in its campaign to topple Muammar Gaddafi, but the military alliance continues to disagree on whether that includes arming rebel fighters.
The pledge, made by Anders Fogh Rasmussen, NATO's secretary general, came during a two-day meeting in Berlin marked by disputes over how to resolve the Libyan conflict and the extent of the alliance's support for the rebels.
Rasmussen added that NATO would maintain "a high operational tempo against legitimate targets" in its mission to enforce a UN-approved no-fly zone over Libya.
Libyan rebels have criticised NATO, which took command of operations over the country on March 31, for not doing enough to prevent attacks on rebel-held towns and cities by forces loyal to Gaddafi, Libya's long-term leader.
"People have been quite upset since NATO took over the command because they thought that NATO has been extremely slow in its air strikes," said Al Jazeera's Hoda Abdel-Hamid, reporting from the rebel stronghold of Benghazi.
Opposition supporters blamed NATO for reverses which have pushed the rebels back towards the east of the country and allowed Gaddafi forces to lay siege to the western city of Misurata, our correspondent said.
US to play 'supporting role'
But the US and some European NATO members on Thursday rebuffed French and British calls for more countries to contribute more actively to the air war.
Nicolas Sarkozy, the French president, and David Cameron, the British prime minister, had agreed on Wednesday that ramping up air strikes against Gaddafi's troops was necessary.
Thursday's meeting revealed rising friction within the alliance with Rasmussen saying that NATO needs more "precision fighter ground-attack aircraft for air-to-ground missions" in order to "avoid civilian casualties".
Hillary Clinton, the US secretary of state, called on NATO to maintain "resolve and unity" but there was no indication that the US would support an increase in the number of air strikes.
Briefing the Reuters news agency, a US official brushed aside complaints, saying NATO commanders had not sought more resources.
Speaking at the White House, state department spokesman Mark Toner said Washington would continue to play a supporting role.
As NATO leaders gathered in Berlin, Ban Ki-moon, the UN secretary-general, called for an immediate cease-fire in Libya and urged Gaddafi to "listen to the call of the international community".
Ban was speaking at a summit on Libya in Cairo hosted by Arab League head Amr Moussa and attended by EU foreign policy chief Catherine Ashton and Jean Ping of the African Union.
"As the fighting rages, the situation will only get worse and the more distant a political situation. We call for an inclusive political process through which the Libyan people can choose their own future," Ban said
Continuing divisions within the international community have been exposed by this week's series of diplomatic initiatives to forge a resolution to the Libyan crisis which kicked off in Doha, Qatar, on Wednesday with the meeting of a "contact group" on Libya.
The group decided to set up a "temporary financial mechanism" to aid the rebels but the question of arming the rebels remains a source of disagreement.
Italy, a former close ally of Gaddafi, who has ruled for 41 years, claims the UN Security Council resolution under which international forces have bombed Gaddafis troops since March 19 permits providing defensive arms to the rebels.
Franco Frattini, the Italian foreign minister, said "either we make it possible for these people to defend themselves, or we withdraw from our obligation to support defending the population of Libya."
"It's very important to broaden the discussion about this point," he said.
But Alain Juppe, the French foreign minister whose country was the first to bomb Gaddafi's forces, came down against arming the rebels.
William Hague, British foreign secretary, said Britain, which was also among the first countries to carry out air strikes in Libya, had been providing non-lethal equipment to the rebels, and would continue to do so.
Belgium expressed opposition to arming the rebels, while Germany insisted that there could be "no military solution".
The final statement from the meeting said that "participants in the contact group agreed to continue to provide support to the opposition, including material support".
Blasts in Tripoli
Meanwhile, there were reports of four blasts in Tripoli on Thursday, which Libyan state television claimed were air strikes. It also reported civilian casualties which have not yet been verified.
Khaled Kaim, the Libyan deputy foreign minister, charged that elements of the Lebanese group Hezbollah were fighting alongside the rebels in the east of his country.
Hezbollah, however, denied sending fighters to aid rebels in Misurata. "Hezbollah denies this accusation and maintains that all such talk is unfounded," said a brief statement released by the group on Thursday.
Gaddafi also said Qatar had sent military trainers to Libya and was supplying the rebels with French-made Milan anti-tank missiles.