Ukrainian security services claimed to have uncovered a Hungarian spy ring gathering information about military activities in Ukraine’s western Transcarpathia region.

Ukraine says it has expelled two Hungarian diplomats hours after the country’s main security agency said that it had arrested two people on suspicion of spying for Hungary by gathering intelligence on Ukraine’s military in the west of the country.

Ukraine said Friday it had exposed a network of Hungarian spies trying to obtain defense secrets in a border region of Ukraine – the first time it said such an operation has been discovered.