Image caption Libyan rebels were described as having 'very limited' ground potential by Mr Fox

Militants within Libya's opposition will have to be marginalised after Colonel Gaddafi is removed from power, says Defence Secretary Liam Fox.

His comment comes after the death of the rebels' military commander was blamed to Islamist-linked militia within the opposition forces.

The UK has recognised the rebels as the legitimate government, but Mr Fox said care was still needed.

"The aim will have to be... to ensure that [militants] are marginalised."

Rebel military commander General Abdel Fattah Younes was found dead on Friday, and rebel minister Ali Tarhouni said he was killed by members of the Obaida Ibn Jarrah Brigade, which is an Islamist group.

History of militants

Gen Younes defected to the rebels in February after serving in the Libyan leadership since the 1969 coup which brought Col Muammar Gaddafi to power.

Mr Fox, speaking to the BBC Radio 4's World This Weekend, said the opposition was made up of a "mixture" of people - and the transition to peace in Libya would have to be carefully managed.

"Of course there are going to be militants in Libya - there are militants across the whole of the Middle East - it would be a great surprise if there weren't some in Libya itself.

"We've known from history that there have been radical elements there. The aim will have to be as we move into the development phase and we go into the growing of the democracy in Libya, to ensure that these people are marginalised - but to pretend they're not there would be unrealistic."

The UK is part of the coalition force which has been conducting operations in Libya since March under a UN mandate authorising military action for the protection of civilians.

Inner circle

Libyan rebels began an uprising against Col Gaddafi in February, but despite Nato's intervention, they have struggled to break a military deadlock.

Mr Fox said: "There's only one message we should be sending to the [Libyan] regime and that is that we have both the military capability and the resolve to continue pursuing and fulfilling United Nations resolution 1973 as long as is required."

But he added that military effort alone - which he said was "very limited" on the ground - would not prompt the downfall of Col Gaddafi.

"The key to the Libyan resolution will be whether or not the close circle around Col Gaddafi recognise there's no point in investing in him - he's a busted flush - and that he will sooner or later have to leave power.

"When the penny drops that that is inevitable, then you're likely to see the sort of change in the political momentum that we've been looking for."

The former head of the British army, General Lord Richard Dannatt, has suggested a new UN resolution could be needed to enable Britain to do more to help the opposition.

But Mr Fox said that would not be necessary: "If other countries believe that there is a need for a ground force, it would require a new UN resolution - I don't think the chances of such a resolution are even remotely possible."