Two NATO jets which were intercepting Russian planes over neutral waters near Estonia briefly violated Finnish airspace, the alliance said.

Two Spanish F-18 jets were scrambled on Tuesday from Estonia's Amari Airbase to intercept Russian aircraft, identified as two MiG-31 jets and one Antonov AN-26 cargo plane, according to the military bloc.

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As they were escorting the Russian planes, the NATO jets violated the airspace of Finland, which is not a member of the alliance.

“In handing over the intercept to the Finnish jets, the Spanish jets accidentally entered Finnish airspace,” NATO spokesman Dylan P. White said.

“NATO’s Air Command has explained the incident to the Finnish Air Operations Centre to improve future coordination,” White added.

Finland’s Defense Ministry said the F-18 Super Hornets violated the country’s airspace southwest of the capital, Helsinki, for around one minute, AP reported.

Russia’s Defense Ministry said that MiG-31 jets and an Antonov AN-26 transport plane were “carrying out a training flight over the neutral waters of the Baltic Sea… in strict accordance with the rules of the use of airspace, without violating the borders of foreign states.”

“During the mission, a NATO F-18 fighter jet approached the Russian air group and followed it for around a minute. After that it changed course and retracted towards the airspace of the Baltic state,” the ministry said.

Intercepts by Russian and NATO aircraft when planes approach each other for identification have become frequent occurrences over the Baltic Sea in recent years, as the bloc beefs up its presence in the area after Russia’s reunion with Crimea and the Ukrainian conflict.

READ MORE: US releases photos showing ‘unsafe’ intercept by Russian jet over Baltic

The sides have repeatedly accused each other of dangerous maneuvering during the procedures.

In June, a Russian Su-27 jet had to ward off a NATO F-16 fighter jet as it closed in on a plane carrying Russian Defense Minister Sergey Shoigu.

Moscow has insisted that its flights over the Baltics never violate national borders and are carried out in strict accordance with international laws that regulate the use of airspace over neutral waters.