Renegade commander Khalifa Haftar was amassing forces near Tripoli on Tuesday in preparation for resuming attacks on the Libyan capital, a military source said.
"Emirati armored vehicles and cannons were spotted advancing to the town of Tarhunah, southeast of Tripoli," the source with the UN-recognized government told Anadolu Agency.
The move came hours after Haftar left Russia without signing a cease-fire deal with head of the internationally recognized government, Fayez al-Sarraj.
"Support for Haftar's forces has been ongoing despite the truce, which proves that he wanted the cease-fire to reorganize his militia," the source said, requesting anonymity.
On Jan. 12, the warring sides of the Libyan conflict announced a cease-fire in response to a call by Turkish President Recep Tayyip Erdogan and his Russian counterpart Vladimir Putin.
In April, Haftar, who is based in eastern Libya, launched an offensive to capture Tripoli from the UN-recognized government.
According to the UN, more than 1,000 people have been killed since the start of the operation and more than 5,000 others injured.
Since the ouster of late leader Muammar Gaddafi in 2011, two seats of power have emerged in Libya: one in eastern Libya supported mainly by Egypt and the United Arab Emirates and the other in Tripoli, which enjoys UN and international recognition.
* Bassel Barakat contributed to this report from Ankara