Russia’s Federal Security Service (FSB) said on Monday that it had prevented an alleged attempt to destroy a train carrying fuel and lubricants in the Moscow region, The Caspian Post reports, citing Anadolu.

According to the FSB, two Russian citizens were detained on suspicion of preparing what authorities described as a “terrorist attack” allegedly carried out under the direction of Ukrainian intelligence services.

The security agency claimed that the suspects had taken an improvised explosive device from a concealed storage location and planned to use it to derail or destroy the train transporting fuel supplies.

The FSB stated that the detained individuals had confessed to the alleged plans and that a criminal investigation has been launched.

Ukraine has not yet issued a comment regarding the allegations.