One Ukrainian soldier was killed and another injured in attacks by pro-Russian separatists in the eastern Donbas region, the Ukrainian military said.

Pro-Russian separatists violated the cease-fire five times on Thursday, according to a statement by the Ukrainian army.

The violations were in Pisky, Zolotoy 4, Travneve, Pavlopil, and Novoluganska regions of Donbas, it added.

The development comes amid rising tensions over Russia’s military buildup on the Ukrainian border.

For the second time this year, Moscow has moved thousands of troops of the border, leading to accusations by the West and Kyiv that it is planning an invasion.

Russia has rejected the claims as “a lie,” but the US, European Union and NATO have persisted with calls for de-escalation and a return to diplomacy, while also warning of sanctions and other countermeasures if Moscow attacks Ukraine.

Russian President Vladimir Putin and his US counterpart Joe Biden also held a two-hour video call last week, in which the Russian leader sought guarantees that NATO will not expand eastward, according to the Kremlin.

“Putin warned … [that] it was NATO that was undertaking dangerous attempts to gain a foothold on Ukrainian territory, and building up its military capabilities along the Russian border,” read a Kremlin statement.

“It is for this reason that Russia is eager to obtain reliable, legally binding guaranties ruling out the eventuality of NATO’s eastward expansion and the deployment of offensive weapons systems in the countries neighboring Russia.”

They also spoke about the lack of progress in implementation of the 2015 Minsk agreements, which were aimed at stopping the conflict between pro-Russia separatists and Kyiv.

The terms of the agreements included a cease-fire in the region, prisoner exchanges, and withdrawal of pro-Russia groups, while also allowing Kyiv to make a constitutional amendment that would give Donbas special status.

However, their implementation has been hindered by repeated allegations of violations by both sides./agencies