The US State Department issued a statement calling the vote illegal.

“The referenda being planned for May 11 in portions of eastern Ukraine by armed separatist groups are illegal under Ukrainian law and are an attempt to create further division and disorder,” State Department Spokesperson Jen Psaki said.

“If these referenda go forward, they will violate international law and the territorial integrity of Ukraine. The United States will not recognise the results of these illegal referenda,” Psaki said.

Psaki said the United States is "disappointed" Russia did not use its influence in the region to postpone the voting, despite Russian President Vladimir Putin's suggestion last week to delay the vote and his claim that Russian forces were pulling back from the Ukrainian border.

Psaki said the United States does not have any indication the Russian military is moving away from the border. She said Russian state media continued to "strongly back" the referendums "with no mention of Putin's call for postponement."

She said the Russian leadership must know that if it continues to destabilize eastern Ukraine and disrupt presidential elections later this month, "we will move quickly to impose greater costs on Russia."

Psaki criticized Russia for not doing enough to prevent the votes.

She expressed US disappointment with Moscow for not using its influence on pro-Russian activists to cancel the referendums even after President Vladimir Putin called for postponement of the voting.

Psaki said the international community should support Ukraine's presidential election scheduled for May 25th.