Former Libyan leader Moammar Gadhafi has urged his remaining fighters to prepare for a long insurgency as the country's new interim rulers met world leaders who pledged $15 billion in financial and humanitarian support to the embattled nation's provisional government.

In an audio message played on Arabic television news channels Thursday, Mr. Gadhafi said his loyalists would fight authority forces and leave the country “engulfed in flames” from guerrilla warfare.

In further comments broadcast later, he accused NATO of seeking to occupy Libya and vowed to prevent oil exports. Calling his hometown of Sirte the “capital of the resistance,” the former leader said he and his followers would never surrender.

In Paris Thursday, France, Britain and other powers pledged to maintain their military operations as long as needed but said the focus is now on reconstruction. British Prime Minister David Cameron and U.S. Secretary of State Hillary Clinton also urged the country's provisional leaders to pursue an inclusive, democratic transition.

Clinton told delegates the United Nations should ease restrictions on Libyan government assets. She said the U.S. had transferred $700 million of the $1.5 billion in assets that were unfrozen for Libya last week.

The European Union announced it was lifting sanctions on 28 Libyan entities, including ports, banks and energy companies.

U.N. chief Ban Ki-moon said the meeting focused on the urgent needs and priorities presented by the National Transitional Council. He said the U.N. would deploy a civilian mission to Libya as soon as possible.

NTC leader Mustafa Abdel Jalil pledged to pursue stability and security.

In her meetings with senior members of Libya's provisional authority, including Jalil, Secretary Clinton said the ailing Lockerbie bomber, Abdel Baset al-Megrahi, “should be behind bars.” U.S. officials said Clinton made it clear that al-Megrahi should never have been freed and that his return to a hero's welcome in Libya remains problematic.

Also Thursday, more countries – notably Romania and Russia – recognized the NTC as Libya's “ruling authority.” Moscow had opposed NATO military intervention in the Libyan conflict.

Authority forces, who have effectively ended Mr. Gadhafi's rule, gave loyalist fighters in Sirte an additional week to surrender. The NTC had originally set a Saturday deadline, saying it would resort to military action if the order was not met. They said negotiations with tribal elders had made progress, and that the extension would also apply to the loyalist strongholds of Bani Walid and Sabha.

NTC officials contend the former leader is hiding in Bani Walid, 150 kilometers southeast of the capital, Tripoli. Other reports suggest he could be in Ghadamis, near the Algerian border.