Nervously eyeing Russian naval maneuvers and military flights near their borders, the three ex-Soviet Baltic states fear they may emerge as the next geopolitical flashpoint after Ukraine in a confrontation that could test their cherished Western ties.

With President Barack Obama heading to Estonia on Wednesday on a visit designed to underline U.S. solidarity with the Baltics ahead of a NATO summit in Wales, the three tiny republics are renewing calls for troops on the ground and military help.

In their comments on the Ukraine crisis, Estonia, Latvia and Lithuania are more hawkish than their Western partners. Anchored in NATO, unlike Ukraine, they have far less cause to fear a full-blown Russian military invasion, but they worry about cyber-attacks and other more stealthy forms of aggression.

"Practically Russia is in a state of war against Europe," Lithuanian President Dalia Grybauskaite said on Saturday, urging Europe to supply Kiev with arms to defeat pro-Russian separatists in eastern Ukraine.

Estonian President Toomas Hendrik Ilves called the Ukraine crisis "an undeclared war".

The Baltic states, which only regained their independence from Moscow in 1991, are acutely aware of their vulnerability to Russian pressure, not least because of their heavy reliance on Russian energy and their sizeable ethnic Russian minorities - both salient factors also in the Ukraine crisis.

"The hardcore anti-Russians, mostly older generations, are generally afraid of tanks crossing the border like in the 1940s," said Catlyn Kirna, a lecturer in international relations at Tallinn University in Estonia, referring to Moscow's forcible annexation of the three countries during World War Two.

"More moderate people fear a loss of independence, falling under Russian influence, they are fearful of Russian money invading politics … and the Russian minority here also causes a lot of fear," she added.

Jitters

Russia certainly seems to be testing the Baltics' vigilance.

Last week, NATO jets were scrambled several times to intercept Russian bombers and fighters approaching Baltic airspace. Latvia spotted Russian submarines 23 nautical miles away from its territorial waters.

And this is not a new pattern that has emerged only since the Ukraine crisis. Last year, NATO scrambled jets more than 40 times to check on Russian jets approaching Baltic borders, compared to once in 2004 when NATO first began patrolling here.

The jitters have extended to the Baltics' neutral Scandinavian neighbors, Finland and Sweden, which are in the EU but not NATO. Finland has accused Russia, its tsarist-era ruler, of violating its airspace three times in less than a week.

Sweden put its top military staff on higher alert last week after having moving quick-response fighter jets to the island of Gotland in the Baltic Sea.

The Baltics' deepest fear is that their NATO allies - with the notable exception of Poland - do not take seriously enough the threat they see from President Vladimir Putin's Russia.

"The Baltic countries aren't worried about immediate Russian actions themselves as much as they fear that their allies in the West do not seem to understand what is going on or ... do not want to take appropriate measures," said Lithuanian political scientist Vykintas Pugaciauskas.

Without a strong Western response, the Baltic states fear Russia could create permanent instability through the use of soft power from energy to cyber attacks.

"The biggest threat at the moment is not an open invasion but so-called 'hybrid warfare', which encompasses informational warfare, cyber attacks, "false flag" attacks or attacks with 'plausible deniability'," said Pugaciauskas.

Possible flashpoints include Kaliningrad, a Russian enclave tucked between Poland, Lithuania and the Baltic sea that is home to Russia's Baltic fleet. Like Ukraine's Crimea region in the Black Sea annexed by Moscow in March, Kaliningrad has no land border with Russia proper.

Lithuanian officials have said Russia could disrupt a new LNG terminal - named "Independence" - due to come online in December as the Baltics' first alternative supply to Gazprom, Russia's giant state-run natural gas company.

Grybauskaite has urged "informational warfare" to counter Russian influence. Many of Lithuania's ethnic Russians watch Russian TV and the president has proposed limiting broadcasts in "languages other than the official languages of the European Union" - a move which would exclude Russian.

"Russia cannot compete with the whole of Europe," said Artis Pabriks, Latvia's former defense minister and now a member of the European Parliament. "But Putin can focus on weaker spots like the Baltics, destabilizing countries economically and then adding to the mix cyber attacks and some ethnic sentiments."

The presidents of Latvia and Lithuania will join their Estonian counterpart in Tallinn to meet Obama on Wednesday. One Lithuanian government official said they would use their talks to "kindle the fire" of his resolve to defend their region.

At the NATO summit in Wales on Thursday and Friday, the Baltic states will press for some kind of deployment of NATO troops, building on increased air patrols already announced by the North Atlantic alliance this year.

But there is skepticism among the Baltics about how much the summit can achieve, given that some key allies have opposed a permanent military base as too much of a provocation for Russia.

"It is important that Obama is coming," said Pabriks. "The risk is he gives a nice speech - but what actually do we do?"

Latvian MEP and former defense minister Artis Pabriks