U.S. Secretary of State Antony Blinken denounced Wednesday a move by Russian legislators to recognize two Russian-supported breakaway regions in eastern Ukraine as independent.

Russia’s lower house voted Tuesday to ask President Vladimir Putin to recognize the Donetsk and Luhansk People’s republics, which declared independence from Ukraine in 2014 after President Viktor Yanukovych was removed from office in the Ukrainian Revolution. 

The European Union urged Moscow not to follow through on the vote by the State Duma. Approval of the vote could further intensify tensions between Russia and Western countries over Russia’s military buildup along Ukraine’s borders that has fueled fears of a Russian invasion.

“Enactment of this resolution would further undermine Ukraine’s sovereignty and territorial integrity, constitute a gross violation of international law, call into further question Russia’s stated commitment to continue to engage in diplomacy to achieve a peaceful resolution of this crisis,” Blinken said in a statement.

Blinken warned that such a move would “necessitate a swift and firm response from the United States in full coordination with our allies and partners.”

Russia has denied any plans to invade Ukraine and has accused the West of inflaming tensions.  

Recognition of the republics could kill the Minsk accords that were reached in 2014 and 2015 after Russian-supported separatists seized territory in Ukraine’s Donbas region. Ukraine has been at war with the breakaway regions since 2014, a conflict that has killed some 15,000 people.

“Kremlin approval of this appeal would amount to “the Russian government’s wholesale rejection of its commitments under the Minsk agreements,” Blinken declared.

Kremlin spokesman Dmitry Peskov said Putin had “taken note” of the request from parliament’s lower house but that it would not be consistent with the Minsk agreements aimed at ending the conflict.

Some information for this report came from Agence France-Presse and The Associated Press.