Ukrainian interim leaders have named popular opposition figure Arseniy Yatsenyuk as the country's new prime minister.
They announced Yatsenyuk's nomination before a large crowd Wednesday in Kyiv's Independence Square. Parliament is expected to consider his name Thursday.
Yatsenyuk is a pro-Western former foreign minister and economy minister. One of his first major jobs would be preventing the Ukrainian economy from collapse.
The White House says it strongly supports Ukrainian leaders as they work to form a multiparty government to represent all Ukrainians. It calls a broad-based government committed to reconciliation the necessary foundation for international aid.
Secretary of State John Kerry says the U.S. is considering $1 billion in loan guarantees for Ukraine.
Kerry also warned Russia Wednesday that it would be a "grave mistake" to intervene militarily in Ukraine.
Russian President Vladimir Putin has ordered an urgent military drill in areas that include the region near the Ukrainian border.
Russian Defense Minister Sergei Shoigu says the drill will check "readiness to deal with crisis situations that threaten the nation's military security."
The Kremlin did not superficially mention Ukraine. It has said it would not interfere in Ukraine's internal affairs. Moscow is a strong supporter of ousted Ukrainian President Viktor Yanukovych.
Ukraine is split between the pro-European west and the pro-Russian east and south.
Anti-government demonstrations erupted in Ukraine when Mr. Yanukovych backed out of a European Union trade deal in favor of economic aid from Russia. The violence escalated last week, leaving nearly 100 people dead.
Ukraine's interim leaders have dissolved an elite security force accused of carrying out some of those deadly attacks on protesters.
Also Wednesday, clashes broke out between pro-Russia demonstrators and supporters of the new government in the southern city of Simferopol -- the capital of Ukraine's Crimea peninsula.
The area is mainly made up of Russian speakers who support Moscow. It is also also home to minority Muslim Tatars who are generally anti-Russia.