The FSB cautioned Russian citizens to refrain from holding unsanctioned meetings with British diplomats, including within the premises of the British diplomatic mission MOSCOW, March 30. /TASS/. Officers of the Russian Federal Security Service (FSB) revealed evidence of intelligence activity by a British diplomat whose accreditation has been revoked, the FSB said. TASS has collected key insights into the situation. Britain’s intelligence activity stopped - As a result of counterintelligence