KIEV (AFP) - Russia, Ukraine and the Organisation for Security and Cooperation in Europe (OSCE) have agreed to restore a ceasefire in eastern Ukraine where Kiev is fighting Russia-backed separatists, the OSCE said.

Kiev has been battling a pro-Moscow insurgency in two breakaway regions bordering Russia since 2014, shortly after the Kremlin annexed Ukraine's Crimean peninsula.

Western countries accuse Russia of having massed around 100,000 troops near Ukraine's borders and accuse Moscow of planning a winter invasion.

The United States has warned the Kremlin of unprecedented sanctions should it launch an attack.

"I was delighted that participants expressed their strong determination to fully adhere to the measures to strengthen the ceasefire agreement of 22 July 2020," OSCE chairman-in-office in Ukraine, Mikko Kinnunen, said in a statement late on Wednesday (Dec 22).

"This is of utmost significance for the people living on both sides of the contact line," Kinnunen added.

The statement was issued following a meeting of officials from Ukraine, Russia and the OSCE - known as the Trilateral Contact Group - and representatives of the self-proclaimed Donetsk and Lugansk People's Republics. The OSCE is the world's largest regional security organisation whose 57 participating states span the geographical area from Canada to Russia.

Kinnunen said that priority was given "to the issues of security" and "compliance with the ceasefire".

A number of ceasefire agreements had been announced but collapsed. The latest was reached in July 2020, but occasional clashes still result in casualties on both sides.

The fighting has claimed more than 13,000 lives.

Ukraine and its Western allies accuse Russia of sending troops and arms across the borders. Moscow has denied those claims.