Secretary of State John Kerry arrived in Ukraine Tuesday to show solidarity with the country's embattled new leaders as they dealt with Russia's occupation of the Crimean Peninsula.
Senior officials aboard Kerry's overnight flight to Kiev told NBC News that the U.S. still believes Russian President Vladimir Putin can take steps to de-escalate the tense situation.
On Monday, Kerry met with President Barack Obama and the rest of the national security team, including Defense Secretary Chuck Hagel, for two hours to discuss the crisis in Ukraine. Obama described the Russian advance as a violation of international law.
A senior Obama administration official told NBC News that the team was looking at "steps we can take with our international partners to further isolate Russia" in a bid to end the crisis.
Kerry's visit is intended to reinforce Washington's backing the new Ukrainian government that only weeks ago ousted pro-Moscow leader Viktor Yanukovych. Days later, Russian forces entered Crimea and surrounded Ukrainian military installations.
Kerry last week offered $1 billion in loan guarantees to Ukraine's new government. The U.S. is also offering technical help to Ukraine's central bank and financial authorities and will help Ukraine to recover stolen assets, a U.S. official told NBC News.
Still, Russian control of Crimea would likely not be easy to reverse. Western-suggested sanctions on Russia, such as questioning Russia's membership in the G-8 economic group and holding out for a diplomatic dialogue proposed by Germany, are an indication of how limited the options were for the U.S. and Europe.
The Associated Press contributed to this report.