Authorities in Tbilisi accused Russia on Tuesday of an “act of aggression” by launching a missile on its territory, BBC and other sources report. According to Georgia authorities, a projectile launched by a fighter plane landed near the village of Tsitelubani on Monday evening but did not explode. Russian authorities quickly dismissed the accusations.

Officials in Georgia said the guided missile was launched as two Russian fighter planes entered the Georgian air space late on Monday. The one-ton missile landed in the backyard of a Tsitelubani house, the Interior Ministry announced.

Interior minister Vano Merabisvili previously told Reuters that it was “an act of aggression” by two planes that entered the Georgian territory from another country.

Officials in Moscow dismissed the accusations that Russian planes entered the Georgian air space on Monday or Tuesday.

It is the most serious incident in the relations between the two countries after Georgia decided last year to expel four Russian officers under charges of espionage. The decision prompted Moscow to apply economic sanctions to its neighbor.