KYIV, May 22 (Reuters) - Ukraine ruled out a ceasefire or concessions to Moscow while Russia intensified an offensive in the eastern Donbas region and stopped sending gas to Finland in its latest salvo in response to Western sanctions and its deepening international isolation.

On the Donetsk frontline, Russian forces were trying to break through Ukrainian defences to reach the administrative borders of the Luhansk region, while further north they continued heavy shelling of Sievierodonetsk and Lysychansk, Ukraine's general staff said in its daily update on Sunday.

The British Defence Ministry said on Sunday that Russia was deploying its BMP-T "Terminator" tank-support vehicles in that offensive.

With only 10 available for a unit that already suffered heavy losses in the failed attempt on Kyiv, however, the ministry said they were "unlikely to have a significant impact".

Ukraine's lead negotiator, speaking to Reuters on Saturday, ruled out a ceasefire or any deal with Moscow that involved ceding territory.

A view of the destroyed village of Moshchun, amid Russia's invasion, Kyiv region, Ukraine May 19, 2022.

Full control of Mariupol gives Russia command of a land route linking the Crimean Peninsula, which Moscow seized in 2014, with mainland Russia and parts of eastern Ukraine held by pro-Russia separatists.

Zelenskiy said he stressed the importance of more sanctions on Russia and unblocking Ukrainian ports in a call with Italy's Draghi on Saturday