The Pentagon estimates there are now about 20,000 Russian troops in Ukraine, as additional forces have gone into the country over the last week.
Rear Adm. John Kirby says Defense Secretary Chuck Hagel spoke with Ukraine Defense Minister Ihor Tenyuh on Friday. He says Tenyuh asked Hagel to consider having the U.S. military provide Ukraine with technical advice, including on humanitarian and disaster relief operations. Hagel said he would consider the request.
U.S. and Western leaders have condemned Russia's takeover of Ukraine's Crimean Peninsula. The Obama administration is moving to impose sanctions on Russia.
Kirby says the U.S. is more concerned about the Russian troops' activities than the numbers.
Crimea's new leader has said pro-Russian forces number more than 11,000 and control all access to the Black Sea peninsula.