Greece on Saturday blamed a "foreign state" for the discovery of a sea drone this week off the Ionian island of Lefkada.

"You saw a drone belonging to a foreign country that was retrieved outside Greek territorial waters a few days ago... we know what it is, and we more or less know what it contains," Defense Minister Nikos Dendias told a conference of the ruling New Democracy party in Thessaloniki.

The craft was found by a fisherman inside a coastal cave on Thursday and was later moved to a naval base on the mainland for inspection, public broadcaster ERT reported.

Military experts made the drone safe for transport to Athens after explosives were found on board, AFP news agency reported, citing a Greek military source.

Drone linked to Ukrainian attacks on Russian oil tankers

The source said the unmanned surface vehicle "resembles" a Magura-class sea drone used by Ukraine's armed forces against Russian ships in the Crimea.

Kyiv has previously confirmed it targeted a Russian "shadow fleet" oil tanker in the past with aerial drones in the Mediterranean.

A source from Ukrainian intelligence claimed that one of the tankers, the QENDIL, was struck in December and "sustained critical damage."

Reuters news agency cited a maritime ⁠security source as saying the drone may have been part ⁠of a ​larger shipment or may have drifted off course after a signal failure.

Edited by: Roshni Majumdar