(Updates with details from Tripoli strike)

BENGHAZI, Tripoli (Reuters) - Forces from Libyas internationally recognised government carried out air strikes on a Tripoli airport after unidentified warplanes attacked one of its allied towns, in escalating violence a day before United Nations peace talks.

Libya is caught in fighting between two rival governments, their local allies and their armed forces. All are battling for control, four years after a civil war ousted Muammar Gaddafi, and the conflict is steadily tipping the North African state into chaos.

Two unidentified warplanes on Wednesday bombed the airport of the western Libyan town of Zintan, which is allied with the internationally recognised government. Electricity systems were damaged but not the runway, a local official said.

Zintan has been hit before by forces from Libya Dawn, which took over Tripoli during fighting in the summer and set up its own self-declared government.

"Two MiG warplanes had targeted the runway but they missed the target. But they bombed the lighting system, which will force us to suspend all flights after sunset," said Zintan aviation official Omar Matoog, without saying who was responsible. "The airport is still working normally."

Hours later, jets from the recognised governments forces, commanded by Gen. Khalifa Haftar, hit Maitiga airport in Tripoli. A source at the airport said the bombs hit an area near the airport runway but caused no major damage.

"We have conducted air strikes on Maitiga airport. We will not stop bombing Maitiga because it is illegal and allows warplanes to take off and bomb Zintan," a spokesman for Haftars forces said.

Fighting and air strikes have escalated even as the United Nations prepares to restart negotiations on Thursday between the two factions in an attempt to broker a ceasefire, form a unity government and put Libya back on track to stability.

Islamist militants, who have gained strength in Libya's turmoil, on Tuesday stormed two oilfields, driving out security forces. Workers had already been evacuated from the Bahi and Mabrouk oilfields earlier.

Ali al-Hassi, a security official allied with the recognised government, said the two oilfields had been destroyed after two days of clashes with the militants. He said fighting was continuing at a third field, Al-Dahra.

"We will move to take back over the fields tomorrow," he said. "Al-Dahra oilfield is still under control of our forces."

Es Sidra and Ras Lanuf oil ports, which handle half of Libya's oil output when operating normally, were shut down in December by the conflict. Libya currently produces around 400,000 barrels of oil per day, compared to 1.6 million before Gaddafi was toppled.

The growing influence of Islamist militants and the escalating conflict between rival governments are worrying Western powers, who fear Libyan chaos will spill over its borders and make the country a safe haven for militants.. (Additional reporting by Ahmed Elumami; Writing by Patrick Markey; Editing by Ralph Boulton, Larry King) ()