Head of Russian spy agency General Igor Korobov dies at 62

The head of Russian military intelligence agency GRU, General Igor Korobov, has died at the age of 62, Russia's defense ministry says.

Gen Korobov, who took up the post in 2016, is said to have died after "a serious and long illness" on Wednesday.

The GRU was this year linked to a nerve agent attack in Britain on ex-Russian spy Sergei Skripal and his daughter.

Gen Korobov is understood to have faced criticism by Russian officials over the failure of the operation.

The attack on Mr Skripal, 66, and his 33-year-old daughter, Yulia, in Salisbury on 4 March led to them requiring weeks of hospital treatment.

The poisoning is alleged to have been carried out by suspects Alexander Mishkin and Anatoly Chepiga, both identified by British authorities as GRU operatives, and "almost certainly" approved by the Russian state.

Russia denies the allegations.

Though General Korobov is one of Russia’s top military officials, very little is publicly known about him. According to his sparse biography on the Defense Ministry’s website, he joined the armed forces in 1973 and joined the G.R.U. in 1985.

The GRU, or Main Intelligence Directorate, is the intelligence arm of the Russian military tasked with carrying out undercover international operations.

Igor Korobov's career in the Soviet, then Russian military, spanned more than 40 years.

He joined military intelligence in the mid-1980s and rose through the GRU ranks to a key position, overseeing strategic intelligence-gathering.

Under Korobov, and his predecessor Igor Sergun, the GRU became the Kremlin's spy agency of choice for a series of high-profile and highly controversial operations. The GRU has been linked to Russia's military operation in eastern Ukraine, to Moscow's meddling in the US election and to a failed coup in Montenegro.

The agency’s activities have put Russia’s adversaries on edge and have provoked a fierce reaction from the West. Russia has been hit with wave after wave of sanctions as a result of its election interference. After Mr Skripal was poisoned, Britain and many allies expelled more than 150 Russia diplomats, many believed to be undercover intelligence operatives.