RAF Typhoons based in Estonia and Swedish Gripen fighters were on Thursday evening scrambled to "intercept" a Russian Il-20 reconnaissance aircraft and a Su-27 fighter jet "flying close to NATO and Swedish airspace", the ministry said.

The Russian aircraft "were not complying with international norms by failing to communicate with the relevant Flight Information Regions (FIRs)" but "remained in international airspace and flew in a professional manner", it added.

On Friday, Typhoons were scrambled again to intercept two Russian transport aircraft flying south from mainland Russia towards Kaliningrad, a Russian exclave wedged between NATO members Poland and Lithuania.

The Typhoons were later "re-tasked to intercept" two Tupolev Tu-22M bombers and two Su-30 fighter aircraft, also flying south from mainland Russia over the Gulf of Finland and the Baltic Sea.

The Russian aircraft were again "failing to liaise appropriately with local FIRs", the ministry said.

Finnish, Swedish, Portuguese and Romanian aircraft were also involved in escorting the Russian aircraft, according to the statement.

"These intercepts are a stark reminder that the RAF is always ready to defend our skies and those of our allies, while the coordinated action by several air forces serves as a clear demonstration of the value of our international alliances," UK Defence Secretary Ben Wallace said.