Russia’s Foreign Ministry said Moscow will not tolerate undeclared intelligence activities by British personnel on its territory, warning that it will respond in kind if London escalates the situation.

The statement came after Russia’s Federal Security Service (FSB) announced it had identified a British diplomat accused of espionage. The FSB said the diplomat was Gareth Samuel Davies, alleging he was sent to Russia under the cover of a second secretary at the British Embassy in Moscow.

The Russian Foreign Ministry added that such activities violate diplomatic norms and stressed that Moscow would take necessary measures to safeguard its national security.