TALLINN, Estonia — Estonian Prime Minister Taavi Roivas on Tuesday urged allies to send over more troops to the region, calling on Germany to take the lead in the effort amid security fears over Russia.

"Estonia sees that a more long-term stationing of European allies in Estonia and the Baltic region could be led by Germany," Roivas said after meeting with German Defence Minister Ursula von der Leyen in Tallinn.

"We are very grateful that German airplanes are protecting Estonian airspace," he told reporters, referring to NATO's Baltic air policing mission.

Sources close to the German delegation said it was surprised by Roivas's remarks because the issue did not come up in the bilateral talks.

They added that Germany was sticking to the 1997 agreement between NATO and Russia that no combat troops would be permanently stationed east of Germany.

Von der Leyen sought to reassure Estonia: "Your concerns are our concerns," she said at a joint press conference with her Estonian counterpart Sven Mikser.

"There is no doubt about solidarity within NATO," she said, stressing the inviolability of NATO's Article 5, which commits the defense alliance to respond collectively if a member is attacked.

Estonian President Toomas Hendrik Ilves had on Sunday called for NATO to send more troops, telling Britain's Daily Telegraph that it is "only reasonable."

Baltic countries Estonia, Latvia and Lithuania have been on high alert since Russia annexed the Crimean peninsula from Ukraine last year and offered alleged military support for pro-Russian separatists battling Kiev government forces in eastern Ukraine.

Russian military maneuvers on Estonia's border have triggered concern in Europe that Moscow could attempt to destabilize countries that were in its orbit during Soviet times.

NATO is thus boosting defenses on Europe's eastern flank with a rapid reaction force of 5,000 troops and command centers in six formerly communist members of the alliance, including one in Estonia.

But a US infantry company numbering 150 soldiers is currently NATO's sole presence in Estonia, and they are not permanent.

Von der Leyen also visited NATO's cyber defense center in Tallinn. She continues her Baltic tour with a visit to Latvia later Tuesday and Lithuania on Wednesday.

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