An emergency meeting between Russia, Ukraine and separatists was under way on Tuesday in an effort to defuse soaring tensions over Russia's troop buildup along the ex-Soviet country's borders.

A spokesman for the Ukrainian delegation, Oleksiy Arestovych, told AFP that progress had been made on efforts to restore a ceasefire that was agreed last July but upended by a recent spate of clashes between Ukrainian troops and Moscow-backed separatists in eastern Ukraine.

The meeting also involving international observers had begun earlier Tuesday.

Ukrainian President Volodymyr Zelensky has called for the resumption of a ceasefire, and said after a meeting with French President Emmanuel Macron last week he hoped the negotiations would be successful.

Following clashes between Ukrainian forces and Moscow-backed separatists in recent weeks, Russia has built up troops along its border with Ukraine, raising fears of a major escalation in the long-running conflict.

The European Union on Monday estimated the number of Russian troops along the Ukrainian border at more than 100,000.

Kiev has been battling pro-Russian separatists in the eastern Donetsk and Lugansk regions since 2014, following Moscow's annexation of the Crimean peninsula.

The conflict, which has claimed more than 13,000 lives, has seen 30 Ukrainian soldiers killed since the start of the year, compared to 50 in all of 2020.