On April 12, debris was found on the beach in Kalvi, Viru-Nigula municipality, after attacks on Russia's Port of Ust-Luga, which is around 30 kilometers from Estonia's border.

Delfi reports that more drone parts were found in subsequent searches, including on April 16 at Turbuneeme, Harju County.

The ISS said the drones were not in Estonian airspace at any time.

Spokesperson Marta Tuul said debris was found in 11 places on the north coast last week. More than one part was found in some places.

"In all 11 cases, it is assumed that these are drones of Ukrainian origin that have been washed up on the Estonian coast from the sea," she added.  

Debris was also found on the western coasts of Estonia and Latvia last year.

Ukraine's attacks on Russia's ports at Primorsk and Ust-Luga have stopped the country from exporting oil by damaging infrastructure.

However, some of the drones have also gone off course on their journeys and landed in Estonia, Latvia, Lithuania and Finland.

Last month, a drone hit a chimney at Estonia's Auvere Power Plant, which is less than 2 kilometers form the Russian border.

A week later, several drones breached Estonia's airspace with one crashing in a field in Tartu County.

Estonian officials asked their Ukrainian counterparts to adjust their flight paths to avoid breaching Estonia's airspace.

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