NATO has urged Muammar Gaddafi to step down and has vowed to keep hitting his forces as long as it takes.
However, the alliance failed to secure firm pledges for new planes it said were needed to finish the job.
As NATO foreign ministers meeting in Berlin struggled to heal a rift over the mission, loud explosions were heard in Tripoli close to Gaddafi's residence. Warplanes were seen swooping over the capital.
The ministers issued a joint statement calling on the Libyan strongman to step down. They also vowed to maintain 'a high operational tempo' against regime targets and 'exert this pressure as long as necessary.'
The pledge came after Britain and France urged NATO allies to intensify the bombing campaign and contribute more warplanes to the mission.
Nearly one month of coalition strikes have failed to shift the balance of power so far.
NATO Secretary General Anders Fogh Rasmussen said the alliance's military commander in Europe, Admiral James Stavridis, told the ministers that more high-precision planes were needed to safely hit targets hidden in urban areas.
'To avoid civilian casualties we need very sophisticated equipment, so we need a few more precision fighter ground-attack aircraft for air-to-ground missions,' Mr Rasmussen told reporters.
Only six out of 28 nations are conducting air strikes, while French officials say France and Britain carry out half of them.
The US, which handed command of the operation to NATO two weeks ago, pulled back its combat jets as it moved into a back-up role. But US planes are still taking part in missions to take out Gaddafi's air defences.
'For our part, the US is committed to our shared mission. We will strongly support the coalition until our work is completed,' US Secretary of State Hillary Clinton told her counterparts.
'We are also sharing the same goal which is to see the end of the Gaddafi regime in Libya,' she said earlier at a meeting with German Chancellor Angela Merkel.
Libya's rebels have urged NATO to step up the air raids.
They said at least 13 people were killed and 50 more wounded today when Gaddafi forces attacked the besieged city of Misrata, which has become a symbol of the resistance.
NATO ministers entered the talks divided over the air raids.
Danish Foreign Minister Lene Espersen, whose country is among those conducting strikes, piled pressure on other allies to do more.
'Denmark is making a huge contribution at the moment and I think it is relevant to discuss burden sharing to put pressure on those countries that haven't started to contribute yet,' she told reporters.
But Spanish Foreign Minister Trinidad Jimenez said her country would not step up its contribution and would only take part in an arms embargo and a no-fly zone aimed at preventing aircraft from flying.
The allies backed a call made by the international contact group on Libya, which met in Qatar yesterday.
'We welcome the outcome of the first meeting of the contact group which took place yesterday in Doha and strongly endorse its call for Gaddafi to leave power,' they said in a statement.
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,' Minister Westerwelle said at the start of the two-day meeting.
