Former Soviet President Mikhail Gorbachev has died at the age of 91, according to Russian media.
His office previously said he was receiving treatment at Moscow’s Central Clinical Hospital.
He died after a long illness, the medical center reported to news agencies.
Image: Mikhail Gorbachev with former US President Ronald Reagan at a meeting in Reykjavík, Iceland in October 1986. Photo: AP
Tributes to the man who brought about the end of the Cold War: Live updates
Russian President Vladimir Putin has expressed his deepest condolences and will send an official telegram to his family, according to a Kremlin spokesman.
One of the most significant figures of the late 20th century, Gorbachev was known for ending the Cold War without bloodshed, but he did not prevent the breakup of the Soviet Union in 1991.
Winning the Nobel Peace Prize in 1990, he forged arms reduction agreements with the United States, including former President Ronald Reagan, and partnerships with Western powers to remove the Steel Curtain that had divided Europe since of the Second World War to bring about the reunification of Germany.
When he became general secretary of the Soviet Communist Party in 1985 at the age of 54, he set out to revitalize the communist system and shape a new union based on a more equal partnership between the 15 republics of the USSR: Russia, Ukraine, Georgia, Belarus, Uzbekistan, Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Moldova, Turkmenistan, Tajikistan, Latvia, Lithuania and Estonia.
But in the space of six years, both communism and the Union collapsed.
He attempted political and economic reforms simultaneously and on an overly ambitious scale, unleashing forces he could not control.
Image: Gorbachev addresses a group of 150 business executives in San Francisco in June 1990. Photo: AP
When pro-democracy protests swept the Soviet-bloc nations of communist Eastern Europe in 1989, he refrained from using force, unlike predecessors who had deployed tanks to crush uprisings in Hungary in 1956 and Czechoslovakia in 1968.
However, the demonstrations fueled aspirations for autonomy in the republics, and the last Soviet leader failed to anticipate the strength of nationalist sentiment.
‘Glasnost’ emboldened nationalists
Gorbachev’s policy of “glasnost” (free speech) allowed previously unthinkable criticism of the party and the state, but it also emboldened nationalists who began pushing for independence in the Baltics and later elsewhere.
His series of extraordinary reforms quickly overtook him and led to the collapse of the authoritarian state.
Read more: People’s boy democratic instinct and boredom with nuclear weapons changed the 20th century How Mikhail Gorbachev became a friend of UK leaders
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0:46 Mikhail Gorbachev meets Margaret Thatcher in 1987
His power was eroded by an attempted coup against him in August 1991, and he spent his last months in office watching republic after republic declare independence until he resigned on Christmas Day of the same year.
The following day, the Soviet Union formally dissolved.
Prime Minister Boris Johnson said he was “saddened to hear of Gorbachev’s death”.
He tweeted that he “always admired the courage and integrity he showed in bringing the Cold War to a peaceful conclusion.”
“At a time of Putin’s aggression in Ukraine, his tireless commitment to open Soviet society remains an example for us all.”
Image: Image: AP
But many Russians never forgave Gorbachev for the turmoil his reforms unleashed, feeling that the subsequent drop in their living standards was too high a price to pay for democracy.
He later said that he had not considered using widespread force to try to hold the USSR together because he feared chaos in a nuclear nation.
“The country was loaded to the brim with weapons. And it would have immediately pushed the country into a civil war,” he said.
Jonathan Eyal of the Royal United Services Institute think tank said: “I didn’t think the Soviet Union was actually an empire in itself of nations that didn’t want to be shackled.
“Like all Soviet leaders, and I dare say like Russian leaders today, he saw the Soviet Union as synonymous with Russia and simply could not understand why nations wanted to be independent.”