The U.S. is rejecting the vote in Crimea even before the results are released.
The White House says Sunday's referendum on succession is contrary to Ukraine's constitution.
The U.S. says the world won't recognize the results of a vote held under what it says are "threats of violence and intimidation from a Russian military intervention that violates international law."
A written statement from the White House calls Russia's actions in Ukraine "dangerous and destabilizing."
The U.S. is urging other nations to "take concrete steps to impose costs" against Russia.
Secession was expected to be approved overwhelmingly.
Read the White House's full statement below:
The United States has steadfastly supported the independence, sovereignty, and territorial integrity of Ukraine since it declared its independence in 1991, and we reject the “referendum” that took place today in the Crimean region of Ukraine. 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.
No decisions should be made about the future of Ukraine without the Ukrainian government. Moreover, this vote was not necessary. The Ukrainian government has made clear its willingness to discuss increased autonomy for Crimea, and the presidential elections planned for May 25 provide a legitimate opportunity for all Ukrainians to make their voices heard on the future of their country.
In addition, Ukraine, the United States, the EU, the OSCE, the UN, and others have called for Russia to allow international monitors into the Crimean peninsula to ensure that the rights of ethnic Russians in Ukraine are being upheld. Russia has spurned those calls as well as outreach from the Ukrainian government and instead has escalated its military intervention into Crimea and initiated threatening military exercises on Ukraine’s eastern border.
Russia’s actions are dangerous and destabilizing. The UN Security Council recognized this in a vote yesterday that only Russia opposed. 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.
In this century, we are long past the days when the international community will stand quietly by while one country forcibly seizes the territory of another. 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.