European Union foreign ministers threatened sanctions on Monday against "spoilers" who obstruct efforts by the United Nations to halt fighting in Libya.

Libya has been in chaos since a NATO-backed revolt ousted Muammar Gaddafi nearly four years ago, with rival governments allied to armed groups fighting for legitimacy in a conflict that threatens to split apart the oil-producing nation.

U.N. Special Envoy Bernadino Leon has been struggling to arrange talks between the main factions and EU foreign ministers said after a meeting in Brussels that the bloc was ready to penalise anyone blamed for thwarting dialogue.

"Those responsible for violence and those who obstruct or undermine Libya's democratic transition must face consequences for their actions," they said in a statement. Ministers gave no details of what sort of sanctions might be imposed.

A confidential discussion paper drawn up by the EU's diplomatic service and seen by Reuters last month set out a range of options for possible sanctions, including imposing a full oil embargo.

A more likely option was to draw up a shortlist of Libyans who could face sanctions, typically visa bans and asset freezes, for undermining peace efforts, it said.

EU ministers on Monday condemned actions that risked damaging Libya's assets, financial institutions and natural resources, saying this might deprive "the Libyan people of the benefits of the sustainable development of their economy."

"The EU believes that the independence and proper functioning of the Central Bank of Libya, and other key financial institutions must be preserved and protected," it said.