Russia has acknowledged a violation of Finnish airspace by a military transport aircraft off Porvoo on Boxing Day last year, the Finnish defence ministry said Wednesday.
The Tupolev 154 aircraft flew in Finnish airspace for about three minutes. A Finnish fighter intercepted the Russian aeroplane. Russia denied the incident at the time.
"The acknowledgement of the airspace violation went according to the standard procedure," said Jyrki Iivonen, director of public policy at the Finnish defence ministry.
Mr Iivonen added he did not regard the Boxing Day incident as serious.
"The situation was probably caused by the fact that the international airspace corridor is so narrow at the point in question. Russia, Estonia and Finland have recently discussed how similar incidents could be averted."
Russian aircraft have violated Estonian and Finnish airspace on numerous occasions in the current decade.