Liam Fox, the British defence minister, says that it is possible that radical Islamist fighters were behind the killing of Abdel Fattah Younes.

"It's not yet clear who actually carried out the killing," he told BBC radio. "Of course there are going to be militants in Libya -- there are militants right across the whole of the Middle East - it would be a great surprise if there weren't some in Libya itself."

"There has always been a mixture of people who make up the opposition forces in Libya...and it will be for the Libyans themselves to sort out exactly how any power structure develops post-Gaddafi," he continued.

"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."