FSB

In a statement the FSB said the two had declared "false information about themselves when receiving permission" to enter Russia.

Russian state-run news agencies reported that the country's security service FSB had accused the diplomat of providing false information on his documents and carrying out espionage activities.

But in Russia it is the FSB that handles espionage cases, including detention and interrogation, and it was Russian FSB officers who searched Tetiana and Oleh's home.

The FSB said the suspect was "guaranteed" a reward of $100,000 and travel to a European country for residence.

State news agencies reported the country's FSB security service accuse the diplomat - whose photo was shown on TV bulletins - of providing false information on his documents and carrying out espionage and sabotage activities.