Witnesses in Libya say a fighter plane was shot down over the rebel stronghold of Benghazi Saturday. Frequent explosions have also been heard in the area.
The renewed violence erupted after Libyan leader Moammar Gadhafi's declared a cease-fire Friday and said he was ready to open channels of dialogue with the rebel opposition.
Libya's state news agency said Saturday Libyan forces were attacked by rebels, which the agency called al-Qaida gangs, and responded in self-defense.
Saturday's fighting comes hours before an emergency international summit in Paris where world powers, including the U.S., the U.N., the Arab League and the European Union, will consider a response to the crisis in Libya.
U.S. President Barack Obama warned Mr. Gadhafi Friday that his forces must stop attacking the Libyan people or face military action. Mr. Obama added that the U.S. will not deploy ground troops.
The U.S. leader also said Mr. Gadhafi's forces must allow humanitarian supplies to reach civilians.
On Thursday, the U.N. Security Council adopted a resolution authorizing a no-fly zone over the country. Nations participating in the no-fly zone enforcement are deploying ships and planes throughout the region.
France's Ambassador to the U.N. Gerard Araud told BBC news that he expected foreign military intervention in Libya within hours of the Paris summit.