Turkish President Recep Tayyip Erdoğan has called on Europe to support its work in Libya, where it is providing military support to the internationally-recognised government, if it wants to end the conflict there.
The GNA led by Fayez al-Sarraj has been under attack since April from strongman Khalifa Haftar's forces based in the east of the country, with fighting killing over 280 civilians and 2,000 fighters.
Erdoğan made his remarks in a column published on the Politico website on Saturday, ahead of a summit in Berlin on Sunday that will try to stabilise the country.
At the meeting, Germany and the United Nations will push rival Libyan camps fighting over the capital, Tripoli, to agree to a truce and monitoring mechanism as first steps towards peace, diplomats and a draft communique said.
Turkey supports the government of Fayez al-Serraj in Tripoli and describes Khalifa Haftar, who heads the eastern Libyan National Army (LNA), as a coup plotter.
"Keeping in mind that Europe is less interested in providing military support to Libya, the obvious choice is to work with Turkey, which has already promised military assistance," Erdoğan wrote.
"We will train Libya's security forces and help them combat terrorism, human trafficking and other serious threats against international security," he added.
Sunday's summit will put pressure on Haftar and the LNA to halt a nine-month offensive against Tripoli after a week-long lull in fighting. But it will not try to broker power-sharing between the two sides, said diplomats briefed on preparations.
Haftar and Serraj are both due in Berlin - along with Erdoğan and the leaders of Russia, Egypt and other Western and Arab powers. Libya has been in turmoil since the fall of Muammar Gaddafi in 2011.
Erdoğan said that if Libya's legitimate government were to fall the militant groups such as Daesh/ISIS and Al Qaeda "will find a fertile ground to get back on their feet".
Erdoğan, who is also due to attend the Berlin talks, wrote in Politico that the Libyan civil war served as a "litmus test" for the EU to show whether its leaders would abdicate their responsibilities and watch the crisis uphold from the sidelines.
"The EU needs to show the world that it is a relevant actor in the international arena," he said.
"The upcoming peace conference in Berlin is a very significant step toward that goal. European leaders, however, ought to talk a little less and focus on taking concrete steps."
Haftar is backed by the United Arab Emirates, Egypt, Jordan, Sudanese and Chadian fighters, and most recently Russian mercenaries. France has also given some support.
In a joint initiative, Turkey and Russia have brokered a ceasefire but Haftar walked away from talks in Moscow this week aimed at finalising the truce agreement.
Erdoğan has accused Haftar of fleeing Moscow and said he would "teach (him) a lesson" if he resumed fighting.
Erdoğan's government backs Sarraj and the Turkish parliament earlier this month approved the deployment of troops to Libya after the signing of security and maritime deals between Tripoli and Ankara.
"To leave Libya at the mercy of a warlord would be a mistake of historic proportions," he said, in a veiled reference to Haftar.
