The European Union’s top officials say the bloc will impose sanctions against those involved in Russia’s recognition of two separatist regions of eastern Ukraine amid fears of a potential Russian invasion of the country.

EU Commission President Ursula von der Leyen and Council President Charles Michel say in a joint statement that the recognition is “a blatant violation of international law.”

The statement adds that the bloc “will react with sanctions” and “reiterates its unwavering support to Ukraine’s independence, sovereignty and territorial integrity within its internationally recognized borders.”