Turkey's President Recep Tayyip Erdogan and US counterpart Donald Trump agreed to "continue their close cooperation" on Libya in telephone talks on Monday, the Turkish presidency said.

Ankara supports Libya's UN-recognised Government of National Accord (GNA) and has stepped up military support to Tripoli against warlord Khalifa Haftar.

The United States officially backs the GNA, but Haftar is supported by Washington's allies Egypt, the United Arab Emirates and Saudi Arabia.

"The two leaders agreed to continue their close cooperation to promote peace and stability in Libya, Turkey's maritime neighbour," the presidency said.

Turkey has helped the GNA, with drones and air defence systems, inflict a series of battlefield setbacks in recent weeks on Haftar's forces who have been fighting to take Tripoli since April last year.

Libya's Prime Minister Fayez al-Sarraj was in Ankara last week, where he said his forces were "determined" to take over the entire country from his rival Haftar.

Last month, US Secretary of State Mike Pompeo criticised the flow of weapons into Libya and urged a ceasefire during a call with Sarraj.