Obama lands in Estonia for talks on Ukraine

US President Barack Obama has arrived in Estonia on a visit apparently aimed at showing Washington's solidarity with the three Baltic states.

His arrival in Estonia comes one day before a NATO summit in Wales, where Russia's involvement in Ukraine is expected to be the main topic.

A high dependence on Russian energy and a presence of Russian minorities in the Baltic states could make them vulerable to attention from Moscow.

At the two-day summit in Wales, the Baltic states will press for some kind of deployment of NATO troops, in addition to increased air patrols already announced by the alliance this year.