France and Germany have spoken with regional leaders in a European push to stop armed escalation in Libya.
But the intervention did little to slow Turkey's drive to send forces to bolster the Government of National Accord in Tripoli and its allied militias.
President Recep Tayyip Erdogan on Monday ordered fast-tracked legislation to approve a military operation on the far side of the Mediterranean.
But French President Emmanuel Macron and Egyptian leader Abdel Fattah El Sisi issued a joint call for "the greatest restraint" by all parties in Libya.
The pair held talks in Paris late on Sunday about the same time that German Chancellor Angela Merkel was on a call with Mr Erdogan.
Contact is set to continue before a trip to Turkey by Mr Macron, Mrs Merkel and British Prime Minister Boris Johnson early next month.
"A further exchange was agreed to strengthen diplomatic efforts," said a government spokesman in Berlin.
Turkey's Foreign Minister, Mevlut Cavusoglu, presented the plan to opposition parties after agreements with the GNA, including a maritime treaty that has provoked uproar around Europe.
Mr Erdogan wants the bill approved by January 9 but the Republican opposition party has declared it will vote against the measure.
"If today Libya becomes like Syria, then the turn will come for the other countries in the region," Mr Cavusoglu said.
"We need to do whatever is needed to prevent Libya from being divided and slide into chaos, and that is what we are doing. It is the legitimate government there that we deal with."
The beleaguered GNA leadership has sought to internationalise the conflict as its territory is encircled by the rival forces of the Libyan National Army under the command of Field Marshal Khalifa Haftar.
Ankara has sent military supplies to the GNA despite a UN embargo, according to a UN report circulated last month.
There are video reports of Syrian fighters allied with Turkey arriving in Tripoli in recent days.
The Speaker of the Libyan House of Representatives, the alternative government in Libya's east, last week warned that the agreements with Turkey would be annulled.
"The Libyan Parliament will take action to ensure the withdrawal of international recognition of this government," Aguila Saleh said during a visit to Cyprus, where he was seeking support for the EU to withdraw its recognition of the GNA.
"It is time to form a new government supported by the Libyan people and Parliament."
Officials loyal to Field Marshal Haftar have warned that the Turkish shipments to Tripoli would be sunk.
Farag Al Mahdawi, the chief of staff of the LNA, said his forces would protect the Libyan coast.
"I have an order. As soon as the Turkish research vessels arrive, I will have a solution," Mr Al Mahdawi said. "I will sink them myself."
Before Christmas, the EU demanded support for the UN-led mediation efforts in the conflict. It called for all sides to attend a peace conference being organised for Berlin in mid-January.
"The EU strongly supports the efforts of United Nations special representative Ghassan Salame and the Berlin process as the only avenue towards relaunching the Libyan political process and to rebuild a peaceful, stable and secure Libya," it said.
"All participants to the Berlin process should engage constructively in bringing about a peaceful resolution to the conflict, that preserves Libyan sovereignty and is negotiated in the interest of all Libyans."
An editorial in the French newspaper Le Monde said infighting between European powers, particularly France and Italy, had contributed to the crisis.
"The spiral of foreign interference in the Libyan conflict threatens maritime balances in the eastern Mediterranean, and the stability of North Africa and the Sahel," it said.
"Europe, with its divisions exacerbated, has deprived itself of all effective action."