LONDON — Three Bulgarian nationals have been convicted by a London jury for espionage on behalf of Russia, marking one of the UK's largest foreign intelligence operations in recent years.

Katrin Ivanova, 43, Vanya Gaberova, 30, and Tihomir Ivanchev, 39, were found guilty of conspiracy to spy at London’s Old Bailey, according to media reports on Friday.

The trio, who lived in London, were part of a spy ring that operated across Europe from 2020 to 2023, targeting Ukrainian soldiers, journalists, and dissidents.

They carried out surveillance on Kremlin opponents, including Bellingcat journalist Christo Grozev, and planned attacks on individuals such as former Russian politician Bergey Ryskaliyev.

Commander Dominic Murphy of London’s Counter Terrorism Command described the case as "spying on an almost industrial scale on behalf of Russia, the Russian state, and Russian intelligence services."

The espionage operation was led by Orlin Roussev, 47, who coordinated the spy ring from a guesthouse in Great Yarmouth, Norfolk.

Roussev employed sophisticated methods, using hidden cameras embedded in everyday objects like ties and Minions toys, and received over €200,000 ($217,000) to fund the activities.

The network, which included six Bulgarians, was reportedly directed by Jan Marsalek, an alleged Russian agent wanted by Interpol.

Marsalek acted as a liaison between Russian intelligence and the spy ring, leading surveillance operations across the UK, Austria, Spain, Germany, and Montenegro.

The convicted trio faces up to 14 years in prison, with sentencing scheduled for May.

Prosecutor Alison Morgan KC described the operation as "extremely sophisticated," while Murphy warned it posed a serious national security threat. — Agencies