Estonia says an officer of its internal security service has been abducted by unknown gunmen and taken across the border to Russia.

The Foreign Ministry says it summoned Russia's ambassador in connection with Friday's incident, which it called "disturbing."

The Estonian Internal Security Service said the officer was investigating cross-border crime when he was abducted at gunpoint on Estonian territory near the Luhamaa border checkpoint.

Foreign Minister Urmas Paet said Estonia expects "to receive all manner of cooperation necessary from Russia in solving this case and bringing the Estonian citizen back to Estonia."