Flight records showed that the aircraft had been inside an international air corridor at the time of the alleged violation, Russian air force spokesman Alexander Drobichevsky said.

"The An-30 plane was found to be within the limits of the corridor," Drobichevsky was quoted by RIA Novosti news agency as saying.

Estonia, Latvia and Lithuania, three former Soviet Baltic states all neighbouring Russia, joined the North Atlantic Treaty Organization on March 29. Their airspace is patrolled by NATO fighters based in Lithuania.

NATO fighters had not been asked to intervene since the alleged violation was brief, Taavi Tuisk, an officer for the Estonian defence forces, said earlier.

Russia had informed Estonia about the flight in line with an open skies treaty, but the plane had no authorisation to enter Estonian airspace, Estonian officials said earlier.

Estonia reported another Russian airspace violation near Vaindloo in March.

WAR.WIRE