Ukraine has asked the United Nations Security Council to discuss on Thursday a bid by Russia’s parliament to recognize self-proclaimed separatists in eastern Ukraine.

The 15-member council was already due to meet on Ukraine’s crisis and discuss the Minsk agreements, which it endorsed in 2015, that are designed to end the separatist war. The meeting comes amid high tensions after Russia massed more than 100,000 troops near Ukraine’s borders in recent weeks, though Russia denies planning an attack.

In a letter to Security Council members seen by Reuters, Ukraine’s Ambassador Sergiy Kyslytsya said the move by the Russian parliament on Tuesday “further aggravated the threats to both Ukraine’s territorial integrity and global security architecture following the ongoing military build-up by the Russian Federation in the vicinity of the borders with Ukraine.”

Russian-backed separatists in the Donetsk and Luhansk regions - collectively known as the Donbass - broke away from Ukrainian government control in 2014 and proclaimed themselves independent, sparking a conflict with the Ukrainian army.

Russia’s lower house of parliament voted on Tuesday to ask President Vladimir Putin to recognise Donetsk and Luhansk as independent. Putin declined to be drawn out on how he plans to respond.

Kyslytsya said the decision undermines the Minsk agreements and asked the UN Security Council to consider the development during Thursday’s meeting in New York.

The UN Security Council has met dozens of times to discuss the Ukraine crisis since Russia annexed Ukraine’s Crimea region in 2014. It cannot take any action because Russia is a veto-power along with France, Britain, China and the United States.