NATO fighter jets deployed on the Baltic security mission intercepted and shot down a Ukraine war drone that strayed into alliance airspace on Tuesday afternoon, with members of the public urged to shelter indoors away from exterior walls and windows.

Dozens of counties straddling the Estonia-Latvia border in north-eastern Europe were put on air raid alert around midday-local-time (0500 Eastern) on Tuesday after a drone linked to the ongoing Ukraine war strayed into NATO airspace. Baltic news portal DELFI cited the Estonian minister of defence Hanno Pevkur who confirmed the event had taken place and who said: “Our air radar and air force systems identified a potential air threat even before [the drone] reached Estonia”.

NATO provides a Quick Reaction Alert force in the Baltic region, officially the Baltic Air Policing mission. Provided by a rotating roster of NATO member states, it provides up to a dozen friendly aircraft to the region ready to immediately react to any incursion 24 hours a day. Per the report, both Romanian and Swedish fighter jets reacted to Tuesday’s alert, and a Romanian F-16 got the kill.

The rogue drone, which is believed to have been launched by Ukraine, was deliberately brought down over an uninhabited area and the debris landed in a marsh in central Est0nia.

The air raid alert lasted approximately one hour. The Latvian Ministry of Defence ordered the public not to approach any drone remains if they discovered them given they could still be dangerous, and told them not to upload any images or videos to the internet, but to turn over such evidence to the police instead. For the duration of the alert, the public were told to “find shelter and stay away from windows and open areas”, and as reported by Die Welt, to shelter in an inner room with no external-facing walls if possible.

Railway services were disrupted as trains were halted where they stood until the danger passed.

The drone arriving in NATO airspace came after a morning of Ukrainian drone strikes on Russian cities bordering European countries. Both St Petersburg on the Gulf of Finland and the city of Pskov, which is close to both the Estonian and Latvian borders had their airports shut for the duration of the strikes.

The geometry of theoretical Ukrainian avenues of attack against the city of Pskov at least suggests the shot-down drone in Estonia today — had it indeed been launched by Ukraine — was intended for Pskov and overflew its target.

In many cases Russia’s invasion of Ukraine has led to battles taking place on the very borders of European NATO, and on several occasions drones and missiles have by accident or design found their way into allied nations, where they have either been shot down or crashed themselves. NATO air defences shot down Russian drones over Poland last year for the first time, prompting Warsaw to accuse Moscow of having deliberately attacked the country with a probing attack, testing the alliance’s air defences.