Mikhail Gorbachev, the last leader of the Soviet Union, dead at 91: Russian media

His death was confirmed by Russian media.

Gorbachev instituted major economic and political reforms known as glasnost ("openness") and perestroika ("restructuring") that ultimately contributed to the collapse of the Soviet Union.

Historians debate how much credit Gorbachev should be given for the fall of the USSR, with many contending that its collapse was inevitable due to inherent structural problems and years of economic mismanagement.

But it's widely agreed that Gorbachev was one of the most significant figures in the 20th century and particularly the past 50 years. Gorbachev oversaw the cessation of the Cold War and the demise of an empire, bringing an end to decades of competition with the US that fostered conflicts around the world and often catalyzed fears of a nuclear holocaust.

In 1990, he was awarded the Nobel Peace Prize for his role in bringing the Cold War to a peaceful end.

Gorbachev came to power in 1985 at the age of 54 far younger than any of his most recent predecessors.

He took a drastically different approach to leadership than those before him, particularly in terms of foreign policy. Gorbachev pulled Soviet troops from a roughly decade-long war in Afghanistan, improved relations with the West, declined to use force in Eastern Europe as nations pushed for democracy, and also pumped the breaks on the nuclear arms race with the US.

In 1987, Gorbachev and President Ronald Reagan signed the Intermediate-Range Nuclear Forces Treaty a landmark pact to eliminate medium-range nuclear weapons.

After surviving a failed coup in 1991, Gorbachev ultimately stepped down in December of that year.

"We live in a new world. The Cold War has ended, the arms race has stopped, as has the insane militarization which mutilated our economy, public psyche and morals. The threat of a world war has been removed. Once again I want to stress that on my part everything was done during the transition period to preserve reliable control of the nuclear weapons," Gorbachev said in his resignation speech.

"Some mistakes could surely have been avoided, many things could have been done better but I am convinced that sooner or later our common efforts will bear fruit, our nations will live in a prosperous and democratic society," he went on to say.

The ex-world leader died as Russia waged an unprovoked war in Ukraine, a former Soviet republic, under the leadership of Russian President Vladimir Putin a former KGB operative.