The death of Mikhail Gorbachev triggered an outpouring of tributes from Western leaders on Wednesday but reaction was muted in Russia, where many blamed the last Soviet leader for the loss of the country's status as a global superpower.

Gorbachev, who changed the course of history by triggering the demise of the Soviet Union and was one of the great figures of the 20th century, died on Tuesday aged 91.

Russian news agency reports said he had died in a central Moscow hospital "after a serious and long illness".

His life was one of the most influential of his times, and his reforms as Soviet leader transformed his country and allowed Eastern Europe to free itself from Soviet rule.

While the changes he set in motion saw him lionised in the West, they earned him the scorn of many Russians after the country was plunged into economic chaos and saw its international influence decline.

President Vladimir Putin, who called the Soviet collapse the greatest geopolitical catastrophe of the 20th century, has spent much of his more than 20-year rule reversing parts of Gorbachev's legacy.

By cracking down on independent media and political opposition, critics say, Putin has worked to undo Gorbachev's efforts to bring "glasnost", or openness, to the Soviet system.

And with the launch earlier this year of a military campaign in Ukraine, he has sought to reassert Russian influence in one of the countries that won its independence when the Soviet Union fell apart.

- 'One of a kind' -

In a letter of condolences published by the Kremlin, Putin said Gorbachev "was a politician and statesman who had a huge impact on the course of world history".

Other senior Russian officials also described Gorbachev as an important figure, but said little of his political accomplishments.

Kremlin spokesman Dmitry Peskov told Russian news agencies it was not yet clear if a state funeral would be held and that a decision would be made later based on the family's wishes.

On the streets of Moscow many refused to comment on his death, one young Russian even asking who Gorbachev was.

Those willing to discuss his legacy, mainly pensioners who fondly remembered the Soviet era, were overwhelmingly negative.

"He was some kind of illiterate politician, who let such a great country fall apart. And anything good he may have done is crossed out by that," said 70-year-old Vladimir Zavkov, as he walked near Red Square.

"So to me he is just a traitor."

But in the West, where Gorbachev was regarded fondly and affectionately referred to as Gorby, he was hailed as an iconic figure.

US President Joe Biden credited Gorbachev with having "the imagination to see that a different future was possible and the courage to risk his entire career to achieve it.

"The result was a safer world and greater freedom for millions of people," he said.

British Prime Minister Boris Johnson said Gorbachev's "tireless commitment to opening up Soviet society remains an example to us all", while UN chief Antonio Guterres called him "a one-of-a-kind statesman".

- 'Man of peace' -

French President Emmanuel Macron praised Gorbachev as a "man of peace whose choices opened up a path of liberty for Russians," and former German chancellor Angela Merkel said he demonstrated how "one single statesman can change the world for the better".

Gorbachev was best known for defusing US-Soviet nuclear tensions in the 1980s as well as bringing Eastern Europe out from behind the Iron Curtain.

He won the Nobel Peace Prize in 1990 for negotiating a historic nuclear arms pact with US leader Ronald Reagan, and his decision to withhold the Soviet army when the Berlin Wall fell a year earlier was seen as key to preserving Cold War peace.

He was also championed in the West for spearheading reforms to achieve transparency and greater public discussion that hastened the breakup of the Soviet empire.

He spent much of the past two decades on the political periphery, intermittently calling for the Kremlin and the White House to mend ties as tensions soared after Russia annexed Crimea in 2014 and launched the offensive in Ukraine earlier this year.

- Backed Crimea annexation -

Gorbachev had supported the Crimea annexation, saying that most people in the peninsula "wanted to be reunited with Russia".

He made no public statements on Russia's military action in Ukraine, though his foundation called for "an early cessation (to) hostilities and immediate start of peace negotiations".

He spent the twilight years of his life in and out of hospital with increasingly fragile health.

He remained a controversial figure and had a difficult relationship with Putin.

Many Russians still look back fondly on the Soviet period, and Putin leans on its achievements to buttress Russia's claim to greatness and his own prestige.

As the USSR collapsed, Gorbachev was superseded by Boris Yeltsin, who became post-Soviet Russia's first president.

From then on, Gorbachev was relegated to the sidelines, devoting himself to educational and humanitarian projects.

- Supporter of free press -

Russia's leading opposition figure -- jailed Kremlin critic Alexei Navalny -- praised Gorbachev in a series of tweets, highlighting his willingness to give up power.

"He stepped down peacefully and voluntarily, respecting the will of his constituents. This alone is a great feat by the standards of the former USSR," Navalny said.

An early supporter of Russia's leading independent newspaper Novaya Gazeta, founded in 1993, Gorbachev donated part of his Nobel winnings to help it buy its first computers.

But the newspaper came under increasing pressure under Putin and suspended publication in late March.

In a tribute published after Gorbachev's death, its chief editor Dmitry Muratov, who last year won the Nobel Peace Prize, hailed him as a man who "put human rights above the state, and valued a peaceful sky more than personal power".