NATO combat jets were activated by the Latvian authorities after a suspected drone entered airspace in the east of the country and then left again, the country's military reported on Sunday.
No further details were provided.
The military also issued an alert to the population. In recent week, explosions have been caused by drones coming down on Latvian territory.
"While Russian aggression in Ukraine continues, there is a possibility of repeated incidents where foreign unmanned aerial vehicles enter or approach Latvian airspace," the military said.
It added that the airspace was being constantly monitored along with the country's NATO allies. Latvia does not possess combat jets and relies on its allies to patrol its airspace.
Earlier this month, empty tanks at a scarcely used oil depot in the eastern town of Rēzekne, some 50 kilometres from the Russian border, were hit by two stray Ukrainian drones.
No one was injured, but the incident sparked a political crisis in which first the defence minister, Andris Sprūds, and then prime minister Evika Siliņa resigned.
Siliņa had forced Sprūds out over repeated drone incidents along the country's borders with Russia and Belarus and his party promptly left the ruling coalition.
Stray drones are thought to result when Russian air defence forces jam Ukrainian drones attacking targets in north-western Russia.
