Libyan rebels occupying major oil ports in the east of the country have said they will not deal with new Prime Minister Ahmed Maetig, branding him "illegitimate".
His predecessor, Abdullah al-Thinni, had reached an agreement with the rebels to reopen four eastern oil ports but so far only the smaller ones Hariga and Zueitina have been handed over to government forces.
Both sides had agreed to hold further talks over reopening the larger Ras Lanuf and Es Sider exports terminals. But the rebels' comments on Wednesday suggested those efforts could hit difficulties.
"Maetig came to power illegally," rebel spokesman Ali Hasi said, without elaborating.
Maetig was sworn in on Sunday after a chaotic election in parliament. Many deputies have challenged his appointment.
The North African country has been mired in turmoil since the 2011 overthrow of Muammar Gaddafi.
Its government and army have struggled to assert authority over a country still awash with arms and rival militias.
A wave of seizures of export ports and oilfields across the desert nation has cut oil output to 250,000 barrels a day, down from 1.4 million in the summer.
In another sign of turmoil, most air traffic at Benghazi airport came to a halt after a fight among ground staff, Reuters news agency reported.
The two main local carriers Libyan and Afriqiyah Airlines suspended flights after a member of the ground staff tried to smuggle two Chadians without travel documents on board one of their flights, airport officials said.
The employee scuffled with a colleague who had tried to stop him, a source at ground handling firm al-Shorooq said.