The head of Russian military intelligence, the organisation accused of being behind the Salisbury novichok poisonings, has died.

General Colonel Igor Korobov had been in charge of the GRU since 2016, following a three decade long career in military intelligence.

Officials said his death came after a "long and serious illness".

Defence official Sergei Shoigu expressed condolences following the death.

A statement notes: "May the blessed memory of a wonderful person, a true son of Russia, a patriot of the Fatherland, Colonel General Igor V. Korobov will forever live in our hearts."

Korobov took over as GRU  head after his predecessor Igor Sergun died suddenly in January 2016 in circumstances described as "unclear".

In March this year, two suspected GRU operatives flew into the UK in what Theresa May's government has said was a mission to assassinate former double agent and former GRU colonel Sergei Skripal.

Russia denies the allegations.

Korobov was sanctioned in December 2016 by the US for "malicious cyber-enabled activities" threatening the national security of the United States.

He was also responsible for GRU operations in Syria.

In 2017 he was awarded the title of Hero of the Russian Federation, the highest state honour.