According to the Prosecutor General’s Office in Kyiv, two of the people arrested were recruited over the internet by a third living in the city of Ivano-Frankivsk in western Ukraine.

A prosecutor spokesman said: “The suspects were preparing to carry out arson attacks on civilian facilities and critical infrastructure in Ukraine, Poland and the Baltic countries.

“As a result of the actions taken, the Ukrainian authorities detained three people and applied preventive measures.

“They are suspected of high treason, preparation for the deliberate destruction of another person's property by arson, and the production, sending and sale of illegally produced holographic security elements, as well as forgery and sale of forged documents.”

During the investigation, police carried out 40 simultaneous searches in the Dnipropetrovsk, Zaporizhia, Ivano-Frankivsk, and Poltava regions, as well as in the capital Kyiv.

Officers seized weapons and ammunition, nine cars and cash worth more than €80,000.

They also seized fake vehicle registration documents, medical certificates, and school leaving certificates.