The Pentagon is looking at additional support measures for its eastern European NATO allies increasingly worried over Russia's military actions in Ukraine, a spokesman said Tuesday.

In particular, the US is planning to beef up training exercises planned for June in the Baltic states, as Moscow hit back at what it called the West's "Iron Curtain" sanctions.

The Pentagon is looking at ways to make the multilateral BALTOPS naval exercise and its land-based counterpart Saber Strike "more robust, using additional assets that are already in Europe; perhaps more aircraft, maybe more ships," said Rear Admiral John Kirby.

US Defense Secretary Chuck Hagel had suggested this possibility to his Estonian counterpart Sven Mikser during a meeting Tuesday at the Pentagon. Hagel was set to meet his Czech counterpart Martin Stropnicky later in the day.

In addition to sending an air force detachment to Poland, the US has also sent four companies of 150 men to Poland and to each of the three Baltic states -- countries that spent five decades under Soviet rule and joined NATO in 2004.

The last contingent of troops arrived Monday in Estonia.

The Pentagon is looking for ways "to keep that presence rotational and persistent throughout the end of this calendar year," Kirby said.

Hagel also had a 45-minute phone call with his Russian counterpart Sergei Shoigu that was "at times terse," Kirby added.

Nevertheless, "both of them agreed that it's time for the tension to decrease and it's time for good, solid diplomatic solutions. I think the difference, though, is on how do you... get at that?" he said.

And contrary to Moscow's declaration that Russian troops that participated in exercises near the border with Ukraine have returned to their barracks, the US said it hadn't "seen a major pullback."

Canada deploys fighter jets for Eastern Europe patrols
Ottawa (AFP) April 29, 2014 - Six Canadian CF-18 fighter jets left for Romania Tuesday to take part in increased NATO patrols over Eastern Europe amid rising tensions with Russia over Ukraine.

The multi-role military aircraft took off from their base in Bagotville, Quebec, at 9 a.m. local time (1300 GMT) as Canadian Defense Minister Rob Nicholson looked on.

In Romania, Nicholson said, the jets will be conducting "training activities in support of (NATO) reassurance measures" in Central and Eastern Europe to demonstrate what another official described as "the strength of Allied solidarity in response to Russian aggression."

France, Britain and Poland have already deployed fighter aircraft to Poland, Lithuania and Estonia, respectively, in response to Russia's military buildup along its border with former Soviet-era satellite Ukraine.

Four warplanes from Denmark are also en route to the region.

NATO announced this month that it would step up its defenses in Eastern Europe due to the growing crisis.

It has also deployed ships in the Baltic Sea and eastern Mediterranean.