A report published by the European Leadership Network states Russian and NATO war games are escalating a climate of mutual distrust. Also Russia, has a habit of conducting large exercises that are not publicly announced beforehand. The most alarming example was a snap exercise in March that involved 80,000 Russian military personnel. The report also states chances are increasing of an accidental military encounter between Russia and NATO. Russian warplanes have flown into NATO airspace on numerous occasions in the past couple years, and in March 2015, Russian bombers reportedly came close to NATO warships exercising in the Black Sea.