France is willing help Libya secure its borders from militant Islamist groups fleeing Mali, Defense Minister Jean-Yves Le Drian said Sunday.

Security officials say the vast deserts of southern Libya are becoming the latest safe havens for al-Qaida linked fighters who fled neighboring Mali after France sent troops there in January to prevent a Islamist coup.

The International Criminal Court on Friday rejected Tripoli's bid to halt its prosecution of slain leader Moammar Gadhafi's son Seif al-Islam for crimes against humanity committed while trying to put down Libya's bloody revolt in 2011.

"The chamber concluded that it has not been sufficiently demonstrated that (Libya's) domestic investigation (covers) the same case that is before the court," the Hague-based ICC said in a statement on the long-awaited decision.

France wants to work with Libya against militant groups on its territory but will not take military action in the country without U.N. backing, President Francois Hollande said on Friday.

Asked about media reports of France preparing an intervention against Islamist groups in southern Libya, Hollande told interviewers from broadcasters France 24, RFI and TV5Monde there were no plans in the works.

With its weak government, porous borders and proliferation of weapons, Libya has been accused of destabilizing its southern neighbors, but analysts say it is wrong to point the finger at Tripoli alone.

Niger's President Mahamadou Issofou has said those behind two suicide attacks in his country on May 23 came from southern Libya.

Three Libyan soldiers died in a bomb attack on their patrol in the eastern city of Benghazi, a military spokesman said on Wednesday, updating an earlier toll.

"An explosive device that was concealed in a rubbish bin blew up near a patrol of the Al-Khandak Brigades," killing one soldier on the spot while the other two later died of their injuries, said Abdullah al-Shaafi.

Mohamed al-Megaryef, the president of Libya's top political body, resigned on Tuesday to comply with a new law banning Gadhafi-era officials from government jobs.

"Everyone must obey the law out of respect for legality and democracy. I tender my resignation... in conformity with the law," Megaryef told a plenary session of the General National Congress.

The Islamists who carried out two attacks last week in Niger which killed 38 people did not come from Libya, as charged by the Niger authorities, Libyan Prime Minister Ali Zeidan said Monday.

Such allegations "are without basis," Zeidan said after meeting EU President Herman Van Rompuy in Brussels.

Niger's president said Monday that attackers who bombed an army base and French-run uranium mine, leaving 38 people dead, entered his country from southern Libya, where he warned further attacks were being planned on Chad.

"For Niger in particular, the main threat has moved from the Malian border to the Libyan border. I confirm in effect that the enemy who attacked us... comes from the (Libyan) south, where another attack is being prepared against Chad," said President Mahamadou Issoufou.

The president of Libya's highest political body will resign on Tuesday after a law was passed banning those who served under the ousted regime of late dictator Moammar Gadhafi, an aide said on Monday.

Mohamed al-Megaryef "will on Tuesday evening submit his resignation before members of the General National Congress," the national assembly, one of his advisers told AFP on condition of anonymity.

The attackers who staged deadly twin bombings at an army base and French-run uranium mine in northern Niger came from neighboring Libya, Niger's President Mahamadou Issoufou said Saturday.

Pointing to the porous nature of the borders in the region, he warned that other "infiltrations" were possible and that Niger needed to examine what other security measures it needed to better defend its territory.