The Lithuanian president sought shelter in an underground bunker after NATO fighter jets were scrambled to intercept a drone that entered the airspace near Vilnius. Thousands of Lithuanians took cover in underground garages when air-raid sirens went off at 9:40 in the morning local time, triggered by an airspace violation near the border with Belarus.

Lithuanian Prime Minister Inga Ruginiene warned that "the war is closer than ever", suggesting that Russia is testing NATO's resolve. The origin of the drone remains unknown. For the first time, a sitting leader of a NATO member state is going into a real bunker - not for an exercise, but because of an actual threat.

Russia also issued threats to the Baltic states, claiming they had planned to let Ukraine carry out attacks from their territory. Russian UN ambassador Vasily Nebenzya said: "NATO membership will not protect you from retaliation." Latvia accused Moscow of deliberately redirecting Ukrainian drones into Baltic airspace.

NATO F-16s were scrambled over Estonia to intercept a suspected Ukrainian projectile redirected by Russian forces. Ukraine apologised for the incident and accused Russia of deliberately steering its drones over NATO territory. NATO Secretary General Mark Rutte praised the alliance's "calm and resolute response". European Commission President Ursula von der Leyen said: "Russia and Belarus bear direct responsibility for drones that threaten lives on our eastern flank."

US troop deployments in Poland and Germany face uncertainty, which is feeding concern among Baltic officials about Washington's commitment to NATO. For a Balkan audience that still remembers the sound of sirens from 1999, this is a reminder that the sound of sirens is the universal language nobody wants to understand - but everyone understands immediately.