A breach within Britain's political and military leadership has opened up as David CameronMuammar Gaddafi, may be a legitimate target while the chief of the defence staff, Sir David Richards, said he was "absolutely not". argued that the Libyan leader,
The clash fed concern on the third day of the air assault that the hastily assembled international alliance is struggling to paper over disagreements about its ultimate war aims, the future role of Nato and the legitimacy of the rebel groups.
There was cabinet anxiety that the scale of the bombardment may strengthen support for Gaddafi in Tripoli and be seen in the Middle East as exceeding the UN security council goal of protecting civilians.
Gaddafi's compound was hit by British missiles on Sunday night in an attempt to weaken his command structure as fighting continued across coastal towns.
Anti-aircraft fire and explosions shook Tripoli again last night, with reports of missile hits on ports and naval facilities to the east and in the capital itself. Police closed a road near Gaddafi's Bab al-Aziziya compound after a blast nearby. Residents watched, some waving Libyan flags.
Just after midnight local time, anti-aircraft batteries opened up again. A mobile unit on the seafront near the Bab Corinthia hotel sent arcs of red tracer fire curving across the sky. No aircraft were visible.
Libyan TV broadcast live pictures of what it called "barbaric crusader bombing" and warned citizens to keep away from ordnance, saying it could contain illegal chemical or biological substances.
Senior cabinet ministers admitted "the emotional optics" of cruise missiles raining down, backed by coalition military briefings, had unwelcome echoes of Iraq. Downing Street is urgently trying to help organise the rebels into a more coherent and visible political and military force.
Cameron won cross-party support for military action from sceptical MPs, but there was disquiet about mission creep, and whether the intervention would end in an unstable partition of Libya. MPs voted overwhelmingly in favour, by 557 to 13, after a six-and-a-half-hour debate.
The rift between Cameron and his defence chief arose after the defence secretary, Liam Fox, said on Sunday that an attack on Gaddafi could be a possibility if it did not lead to civilian casualties. When asked whether Gaddafi was a legitimate target, Sir David replied: "Absolutely not. It is not allowed under the UN resolution and it is not something I want to discuss any further."
Cameron told MPs: "The UN resolution is limited in its scope and explicitly does not provide legal authority for action to bring about Gaddafi's removal by military means. We will help fulfil the security council aims, and leave it to the Libyan people to determine their government and their destiny, but our view is clear that there is no decent future for Libya with Colonel Gaddafi remaining in power."
Later Cameron's spokesman argued that it was lawful to target Gaddafi if he was seen as organising the threat to Libyan civilians, pointing out that the security council's objective was to protect civilians.
A summary of the legal advice given to the cabinet by the attorney general, Dominic Grieve, was published. It implies that attacks on Gaddafi are lawful if he poses a threat.
The head of the US Africa Command, General Carter F Ham, said attacking Gaddafi was not part of his mission.
A French spokesman said that even if the Libyan leader's exact location were known, he would not be targeted. However, the French foreign minister, Alain Juppé, said he hoped the allied attacks would topple Gaddafi. "It is very probable that faced with the increased fragility of the regime, it falls apart from within."
Barack Obama, on tour in South America, echoed the dispute in London, saying there was no contradiction between the Pentagon saying removal of Gaddafi was not a goal and the White House saying it was. He said the aim of the military was restricted to fulfilling the mandate of the UN, which was to protect civilians, but the White House and the state department was working for Gaddafi's removal.
"I have also stated that it is US policy that Gaddafi has to go and we have a wide range of tools to support that policy," Obama said, making it clear he had in mind diplomatic pressure. Obama said when a leader lost legitimacy and turned his army on civilians, the international community could not respond with "empty words".
Republicans, while backing intervention to prevent a massacre in Benghazi, objected to a lack of proper consultation with Congress and a lack of a clear mission. Obama said he had expected to transfer command from the US to Europe within days, but that is being held up by a Nato dispute involving Turkey, which objects to the scale of the attack on Libya.
Ham said he was not worried about mission creep. Most of the action to destroy Gaddafi's air defence systems and push back his forces from Benghazi had taken place in the first 24 hours and he did not anticipate further action on that scale.
Ham said he also saw coalition partners taking a bigger share in the days ahead. There were 60 sorties on Sunday and 70 on Monday, in which about half the planes involved were non-American. New members were joining the coalition, with Canadian and Belgian forces being added, and more were expected to follow.
A total of 12 Tomahawk missiles had been fired in the past 24 hours, he said, aimed at a Scud missile base and a regional command centre, plus a repeat attack on an air defence system. US, British, French, Italian and Spanish planes were over Benghazi and he expected the no-fly zone soon to extend along the coastline.
Ham insisted the mission was not to help the rebels, only to protect civilians. But Mark Toner, the state department spokesman, said regime change was an aim after Gaddafi's failure to honour the ceasefire he declared last week. "What we are trying to do is convince Gaddafi and his regime to step down from power … That remains our ultimate goal."