The UN's special representative for Libya told the Security Council that France's offensive in Mali could drive Islamic rebels into Libya.
The Associated Press reported Tarek Mitri said "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."
More from GlobalPost: Mali: Life under Al Qaeda
UN peacekeeping chief Herve Ladsous said the rebels fled to northern Mali with looted heavy weapons after the fall of Libyan dictator Muammar Gaddafi in 2011.
The Islamists have links to al-Qaeda.
Mitri said that he was also concerned about the continued detention of 7,000 people, still being held in Libya.
Reuters reported French-backed Malian troops searched houses in Gao and Timbuktu on Tuesday, where they found arms and explosives brought in by the rebels.
France's offensive into its former West African colony has prompted an international crisis which donors estimate will cost almost $1 billion, according to Reuters.