Spain has asked Israel to explain why it gave a Spanish-made helicopter drone to the Russian PM as a gift.
Agriculture Minister Uri Ariel gave the drone - used for crop inspections and costing €50,000 ($53,000) - to Dmitry Medvedev early this month.
Spain prohibits the export of sensitive technologies to certain countries. The drone's export licence had a clause requiring Spanish permission to do so.
Israel said the gift had been approved by "relevant professional officials".
The export licence for the drone lists Israel's Volcani Centre as its final user.
It was made by Spanish company Alpha Unmanned Systems.
Spanish media reports said it had US-made cameras, installed by Israel after it was acquired from Spain.
Russia is under European Union sanctions, stemming from its annexation of Crimea from Ukraine in 2014.