German police have arrested three people, suspected of espionage, reports German media.
The arrested, three men from Russia, Ukraine, and Armenia, are suspected of being agents working "on behalf of a foreign intelligence service". They are alleged to have spied on a Ukrainian citizen living in Germany.
They were caught in Frankfurt on Wednesday, when they were staking out a café where their target was thought to be.
The prosecution authority will not disclose which nation's intelligence service is involved.
