Vice President Joe Biden, left, and Lithuania's President Dalia Grybauskaite shake hands prior to their meeting at the Presidential Palace in Vilnius, Lithuania, Wednesday, March 19, 2014. Biden arrived in Vilnius for consultations with Grybauskaite and Latvia's President Andris Berzins, a few hours after Russian President Vladimir Putin approved a draft bill for the annexation of Crimea, one of a flurry of steps to formally take over the Black Sea peninsula.

VILNIUS, Lithuania — After moving to annex Crimea, Russian President Vladimir Putin insists he has no intention of invading other regions in Ukraine, much less other nations. But leaders in Russia's backyard aren't so sure, and they're looking to Vice President Joe Biden for assurances that the U.S. has a plan to prevent that from happening.

Biden was meeting in this Baltic capital today with the leaders of Lithuania and Latvia, two small countries that, like Ukraine, border Russia. Almost 10 years to the day after Lithuania and Latvia joined NATO, the Baltics are suddenly plunged into the type of eerie concern about foreign aggression they may have thought they'd left behind at the end of the Cold War.

A day after promising more sanctions and regional military exercises to send a stern signal to Putin, Biden was making the case that the U.S. stands ready to defend nations like Latvia, Lithuania and Estonia whose NATO membership entitles them to a defensive response from the U.S. and others.

“Have no doubt: The United States will honor its commitment. We always do,” Biden said Tuesday in Warsaw, Poland, which shares a border with both Russia and Ukraine.

Still, the entire region is reeling from Moscow's move to absorb Crimea into its orbit. Tough talk, sanctions and travel bans have not been enough so far to dissuade Putin and his military from seizing control of Crimea and then, after a Crimean referendum that the West has condemned as illegal, declaring it part of Russia. Other countries watching warily are concerned they could be next.“The punishment doesn't fit the crime, and the Baltic states and central European states know this,” said Michael Geary, a European relations analyst at the Wilson Center, a Washington think tank. “They're worried that the U.S. response has been mediocre at best, and there's a palpable sense they need reassurance. Will they be protected in the event of further westward march by Russia?”Yes, they will, Biden was seeking to assure the Baltic leaders as he closes out a two-day trip to the region intended to send a stern signal to Putin.Biden and his team sat down for a series of meetings with Lithuanian President Dalia Grybauskaite and Latvian President Andris Berzins. “The situation is alarming,” Grybauskaite said.

Joe Biden