TRIPOLI - A fighter plane was shot down in the rebel-controlled Libyan city of Benghazi Saturday morning, pan- Arab Al-Jazeera TV reported.

A plane was heard flying overhead, which was pretty close to the center of Benghazi, and then it was hit down in flames, Al-Jazeera quoted witnesses as saying.

Meanwhile, witnesses said that an artillery bombardment hit the center of Benghazi on Saturday, said Al-Jazeera, adding troops loyal to Libyan leader Muammar Gadhafi have entered outskirts of Benghazi.

In the meanwhile, thousands of Libyans were fleeing the western outskirts of the rebel stronghold of Benghazi, Libya's second largest city, said Al-Jazeera.

In a statement posted by the official Jana news agency on Saturday, the Libyan government said its armed forces responded in self defense to attacks from the rebels.

The government also said the rebels violated the UN resolution by using a helicopter and a fighter jet to bomb Libyan armed forces.

The statement, however, did not say the Libyan air force bombed Benghazi nor confirm the downing of a war plane over the rebel- held city.

As it is hard for journalists to get access to the frontline, the Libyan government's accusations against the rebels can not be independently verified.

Libya authorities on Friday declared to halt all military operations in line with a UN resolution that imposed a no-fly zone over the North African country, while the rebels accused that the attacks of the pro-Gadhafi forces have continued.

Meanwhile, some world powers are preparing to militarily support the UN-backed no-fly zone despite Tripoli's ceasefire declaration.

In Paris, an international summit is being held Saturday, grouping UN chief Ban Ki-moon, leaders or high-level decision- makers from several Western and Arab countries and representatives of the European Union, the Arab League and the African Union.

Attendees are expected to discuss detailed plans to enforce Thursday's UN Security Council resolution on the Libya situation at the conference, which is being hosted by French President Nicolas Sarkozy, a leading advocate of military intervention.

The resolution "demands the immediate establishment of a ceasefire and a complete end to violence and all attacks against, and abuses of, civilians," and authorizes the imposition of a no- fly zone over Libya.

NATO ambassadors are also expected to meet over the weekend to fix details about the alliance's participation after they reached consensus Friday on supporting the no-fly zone.