If it holds, the ceasefire would be the country's first break in fighting in months, and the first brokered by international players. It comes as Libya is on the brink of a major escalation, with foreign backers of the rival Libyan governments stepping up their involvement on the ground.
A spokesman for the self-styled Libyan Arab Armed Forces, which are led by ex-general Khalifa Hifter, said in a video statement that the ceasefire would take effect starting early Sunday. Spokesman Ahmed al-Mosmari said any violations of the ceasefire by their fighters would be dealt with "severely."
It was not immediately clear if Hifter would also agree to a withdrawal of forces from around the capital. His rival, Fayez Sarraj, who is prime minister of the U.N.-supported government in Tripoli, had demanded previously such a pull out as the truce's condition. Libya is governed by dueling authorities, one based in the east and one in Tripoli in the west, led by Sarraj. Each rely on different militias for support.
Hifter's eastern-based forces launched a fresh offensive to take the capital in April, sparking international efforts to try to contain the crisis in the North African nation.
Earlier this week, Turkish President Recep Tayyip Erdogan and his Russian counterpart Vladimir Putin released a joint statement after a meeting in Istanbul calling for a Jan. 12 truce. They did not specify what the conditions would be.
The calls for a ceasefire between the warring eastern and western Libyan forces came amid a flurry of diplomatic activity by European powers. The west-based government welcomed the calls for a stop to the fighting. A spokesman for Hifter's forces said initially that they would continue their push to take the seat of their rivals, Tripoli, from "terrorist groups."
A U.N. peacekeeping body has welcomed the development. The United Nations Support Mission in Libya said in a statement that it hopes all parties will demonstrate "complete adherence" to the agreement to stop the violence. The United Nations and European powers, along with Libya's allies in the region, have been calling for a peace summit to happen in Berlin early this year that would bring together the leaders of the rival governments.
The east-based government, backed by Hifter's forces, is supported by the United Arab Emirates and Egypt, as well as France and Russia. The western, Tripoli-based government receives aid from Turkey, Qatar and Italy.
The fighting has threatened to plunge Libya into violent chaos rivaling the 2011 conflict that ousted and killed longtime dictator Moammar Gadhafi.
In the decade since the ouster and death of Gadhafi, the oil-rich nation has increasingly become a setting for proxy battles between regional players vying for influence in the Mediterranean region. Russia and Turkey, with their support of the eastern- and western-based Libyan governments, have become the latest additions.