President Barack Obama is in Estonia to reassure it and the other Baltic states that the United States will help defend them against any Russian aggression. Obama arrived early Wednesday for a full day of meetings, first with Estonia's president and later with leaders of the other Baltic republics, Latvia and Lithuania.
Obama stopped here on his way to the NATO summit in Wales, where Russia's aggression in Ukraine will be the main topic and where Obama will work to step up pressure on Russia to stop interfering in Ukraine.
Last week, Obama indicated his stop in Estonia would be aimed at reassuring the nervous Baltic states.
"Part of the reason I’ll be going to Estonia is to let the Estonians know that we mean what we say with respect to our treaty obligations," said Obama.
His visit comes as fighting continues in eastern Ukraine between Ukrainian forces and Russian-backed rebels. Reports that Russia has sent troops and equipment across the border to reinforce the rebels have further raised concerns among Baltic nations formerly under Moscow's control that see themselves as vulnerable to Russia.
Estonia, like Ukraine, is a former Soviet republic with a large Russian minority. Also like Ukraine, the country has gradually pushed away from Russia's sphere of influence and developed trade and cultural ties with western Europe.
Unlike Ukraine, Estonia is a member of NATO and the United States has an obligation to help defend it.
White House officials say President Obama's visit is meant to send a message to Russia that it should not think of interfering with Estonia in the way it has been doing with Ukraine.
Obama has no plans to offer lethal U.S. military support to Ukraine. Instead, the U.S. leader will push for more sanctions after the earlier round - while hurting the Russian economy - failed to sway Russian President Vladimir Putin.
"President Putin and Russia have repeatedly passed by potential off ramps to resolve this diplomatically. And so in our consultations with our European allies and partners, my expectation is, is that we will take additional steps primarily because we have not seen any meaningful action on the part of Russia to actually try to resolve this in diplomatic fashion," said Obama.
NATO allies this week will consider setting up a readiness force and positioning military equipment in eastern Europe to deter any Russian aggression.
While President Obama has ruled out sending U.S. forces to confront Russia in Ukraine, the United States since April has been rotating troops to Estonia to take part in training exercises.
Obama was scheduled to speak to those troops at Tallinn airport before departing for Wales late Wednesday.