Updated

The U.N.'s special representative for Libya warned the Security Council on Tuesday that France's military offensive in northern Mali may drive Islamic insurgents out and across the porous borders with Algeria and back into Libya.

U.N. officials including peacekeeping chief Herve Ladsous said last year that the hard-line Islamic occupation of northern Mali was partly triggered by the downfall of Libyan dictator Moammar Gadhafi in 2011, as well-trained militiamen fled into Mali with looted-heavy weapons, driving back the Malian army.

U.N. special representative for Libya Tarek Mitri told the Security Council that "the opposition of armed radical groups to the military intervention in Mali may exacerbate the situation (in Libya) given ideological and/or ethnic affiliations as well as porous borders in Libya."

French and African land forces are battling al-Qaida-linked Islamists in northern Mali, while a renewed bout of unrest has gripped Egypt following the two-year anniversary of the revolution that toppled strongman Hosni Mubarak.

In addition, a Jan. 16 terror attack on Algeria's Ain Amenas natural gas plant in the Sahara ignited a four-day siege with Algerian forces in which at least 37 hostages and 29 militants were killed. An al-Qaida-affiliated group has claimed responsibility for the attack.

Mitri said that he was also concerned about the continued detention of several thousand people as result of the Libyan conflict.

He told reporters that some 7,000 detainees are held in Libya, most of them in cells run by the anti-Gadhafi revolutionary brigades.

"There have been cases of torture in the past," but conditions are improving as more prisoners are transferred to state-controlled prisons. "There are still a few cases of torture, but only a few," Mitri added.