The White House said Sunday that the U.S. and its allies would not recognize a referendum in Crimea to secede from Ukraine, as early exit polls showed that more than nine in 10 voters there favored joining the Russian Federation.

“This referendum is contrary to Ukraine's constitution, and the international community will not recognize the results of a poll administered under threats of violence and intimidation from a Russian military intervention that violates international law,” White House press secretary Jay Carney said.

“No decisions should be made about the future of Ukraine without the Ukrainian government,” President Obama’s top spokesman added.

As expected, early snapshots show that those in the Crimean region voted overwhelmingly to join Russia, according to exit polling.

Russian President Vladimir Putin has vowed not to act on Ukraine until the results of the referendum are finalized, despite the prospect of economic sanctions from the Obama administration.

Secretary of State John Kerry also called Russian Foreign Minister Sergey Lavrov on Sunday to discuss the Ukrainian crisis.

“Secretary Kerry reaffirmed that the United States considers the ongoing referendum illegal under Ukrainian law and restated that the United States will not recognize the outcome,” a senior State Department official said. “He raised strong concerns about the Russian military activities in Kherson oblast yesterday and about the continuing provocations in eastern cities in Ukraine.”

Russian forces are mobilizing along the Ukrainian border, and western officials fear that Putin will ultimately order his troops to move further eastward into Ukraine. Putin has denied such assertions.

The Obama administration has pledged to initiate sanctions in coming days, potentially as early as Monday.

“As the United States and our allies have made clear, military intervention and violation of international law will bring increasing costs for Russia — not only due to measures imposed by the United States and our allies but also as a direct result of Russia’s own destabilizing actions,” Carney said.

“We call on all members of the international community to continue to condemn such actions, to take concrete steps to impose costs and to stand together in support of the Ukrainian people and Ukraine’s territorial integrity and sovereignty,” he added.