The head of Russia's GRU military intelligence agency that the West has blamed for a string of brazen attacks died on Wednesday after "a serious and long illness," the Russian Defense Ministry said.
State news agency TASS cited the ministry as saying Igor Korobov, 62, who ran the spy agency since 2016, had been made a Hero of Russia for his service in the post, the highest state award.
Britain has accused the GRU of attempting to poison former Russian spy Sergei Skripal and his daughter with a nerve agent in the city of Salisbury, the Netherlands has accused it of trying to hack the global chemical weapons watchdog, and U.S. intelligence agencies say it tried to hack the 2016 presidential election.
Russia denies all those allegations.
Speculation about Korobov's fate had been growing since an unconfirmed Russian media report that he had been summoned by President Vladimir Putin after the Skripal affair and severely criticised for the operation which left the Skripals alive and the GRU a target of mockery in the Western media.
Korobov was absent from a ceremony in Moscow this month where Putin and other senior officials celebrated the centenary of the GRU, with the Russian leader praising its skill and "unique abilities."
Operatives of the agency, widely known by its old acronym of GRU, set an example for a future generation of military spies, said Putin, himself a former intelligence officer, citing their readiness to sacrifice everything "for the motherland."
Korobov's death paves the way for Putin to appoint a successor to head an agency that intelligence experts say has stepped up its covert missions as tension mounts between Russia and the West, which has imposed sanctions on Moscow over its annexation of Ukraine's Crimea.
Asked last month if there would be a shake-up at the defense ministry in the aftermath of the Skripal affair, the Kremlin said the low quality of the allegations leveled at GRU did not justify such changes.
The United States included Korobov's name on a March sanctions blacklist of people believed to have helped "undermine cyber security on behalf of the Russian government."
Korobov was a Soviet military veteran who served in the air force and, according to his official biography, began working for the GRU in 1985.
The GRU, founded as the registration directorate in 1918 after the Bolshevik revolution, is one of Russia's three main intelligence agencies, alongside the domestic Federal Security Service and the SVR Foreign Intelligence Service.