President Abdel Fattah al-Sisi has denied reports that the Egyptian air force carried out air strikes in Libya on Islamist militiamen around the capital's airport.
Libyan Islamists have charged that Egypt and the United Arab Emirates were behind a raid around Tripoli airport on Friday night that killed 13 fighters.
Fajr Libya, a coalition of Islamist militias, said yesterday it had captured Tripoli's battered international airport from nationalist militiamen.
The announcement came a day after an unidentified warplane raided Islamist positions around the airport, killing 13 fighters, a Fajr Libya spokesman said.
The fall of the airport would be a major defeat for the nationalist fighters from Zintan, southwest of Tripoli, who have held it since the overthrow of long-time dictator Muammar Gaddafi in 2011.
Meanwhile, unidentified war planes attacked targets in Libya's capital Tripoli after forces from the city of Misrata said they had seized the main airport.
Tripoli residents heard jets followed by explosions at dawnbut no more details were immediately available.
In recent weeks Libya has seen the worst fighting since the NATO-backed campaign to oust Muammar Gaddafi in 2011.
Renegade general Khalifa Haftar has declared war on Islamist-leaning forces, part of growing anarchy in the oil producer.
His forces claimed responsibility for air raids on Tripoli on yesterday and last Monday, targeting a group called Operation Dawn.
But this group, consisting mainly of fighters from Misrata, said on Saturday that it had captured Tripoli's main airport from a rival faction from Zintan in western Libya.
In the campaign to overthrow Gaddafi, fighters from Zintan and Misrata were comrades-in-arms. But they later fell out and this year have turned parts of Tripoli into a battlefield.
Libya's neighbours and Western powers worry Libya will turn into a failed state as the weak government is unable to control armed factions .
Libya faces the prospect of two competing parliaments, after the claimed Misrata victory at Tripoli airport.
In a challenge to the parliament elected on 25 June, as pokesman for Operation Dawn called for the old General National Congress (GNC) to be reinstated.
Misrata forces have rejected the new House of Representatives, where liberals and politicians campaigning for a federalist system have made a strong showing.