The failure by Libya’s government to keep order at the border crossings, vital supply routes for the Libyan capital, underlined the challenges facing the new leadership which took over from ousted leader Muammar Qaddafi.

“The crossing is now open,” Abd Essalem Chandol, a Tunisian official, told Reuters by telephone from the main crossing point at Ras Jdir.

“Tunisian security forces decided to ... return to supervise the crossing again after adequate safeguards were put in place under the supervision of regular troops on the Libyan side,” he said.

Tunisian authorities also reopened the second, smaller crossing, at Dehiba further to the south.

“Dehiba crossing was opened suddenly this morning ... Some Tunisians have begun to cross into Libya,” said a local resident who gave his name only as Ali.

Libya’s interim National Transitional Council has struggled to rein in the myriad armed militias which wield power on the ground, in the absence of a fully functioning army or police force.

Tunisian officials have said Libyan militia members had threatened border guards and that there had been a gunfight with militiamen who tried to cross illegally into Tunisia.

Libyan Deputy Prime Minister Mustafa Abu Shagur said earlier this month the authorities would work to secure the border crossings and bring the militias there under control.