NATO fighter jets on Monday shot down a drone that entered Latvian airspace from Russia, the Baltic nation's army said, the latest in a series of such security incidents along Europe's eastern border regions.

The drone's origin was not immediately known.

Ukraine has in recent months stepped up its long-range drone attacks on Russia, including in the Baltic Sea area, where several Ukrainian military drones have strayed into the airspace of Finland, Latvia, Lithuania and Estonia.

"Allied fighter jets successfully shoot down a drone flying into Latvian airspace!," Latvia's army said in a post on social media X.

Authorities earlier on Monday warned people in the eastern Latvian regions to seek shelter indoors due to the threat. The alert ended when the drone was shot down, the army said.

Military drones straying into the airspace of Russia's neighbours have been stoking concerns that the war in Ukraine is spilling over into NATO's northern borders.

Last month a NATO military jet shot down a suspected Ukrainian drone over Estonia.