Nato fighter aircraft were scrambled to intercept Russian military aircraft flying near Estonian airspace on 1 August.
The two Spanish F-18 Super Hornets, which were conducting the Nato air policing mission in the Baltic States, blocked two MiG-31 fighter jets and an AN-26 transport plane from Russia.
Nato was quoted by Reuters as saying: "Two Spanish F-18 jets assigned to Nato’s Baltic Air Policing mission scrambled from Estonia's Amari Air Base.”
The fighter jets are said to have violated Finnish airspace while trying to intercept Russian aircraft near Estonia, Associated Press reported.
The territorial violation took place in the Gulf of Finland, south of Upinniemi, according to a statement by Finland’s Ministry of Defence.
Nato spokesman Dylan P White was quoted by Associated Press as saying: “In handing over the intercept to the Finnish jets, the Spanish jets accidentally entered Finnish airspace.
“Nato’s Air Command has explained the incident to the Finnish Air Operations Centre to improve future coordination.”
An investigation into the suspected territorial violation is being carried out by the Finnish Border Guard.
Russian military and civilian aircraft have violated the international space over Finland several times so far, according to Associated Press.
Nato is increasingly intercepting Russian aircraft in recent years amid tensions over Russia's involvement in the Ukraine crisis, Reuters reported.