Mikhail Gorbachev was mourned in the West on Wednesday as a towering statesman who helped to end the Cold War, but his death received a cool response in Russia, engaged in a war with Ukraine to regain some of the power it lost when he presided over the Soviet Union's collapse.

Gorbachev, the last Soviet leader, died at the age of 91 in a Moscow hospital on Tuesday after two years of serious illness.

In six heady years between 1985 and 1991, he forged arms treaties with the United States, and partnerships with Western powers to remove the Iron Curtain that had divided Europe since World War Two and bring about the reunification of Germany.

But his internal reforms, combining economic and political liberalisation, helped weaken the Soviet Union (USSR) to the point where it fell apart - a moment that President Vladimir Putin once called the "greatest geopolitical catastrophe" of the 20th century.

U.S. President Joe Biden called Gorbachev "a man of remarkable vision" and, like other Western leaders, emphasised the freedoms he introduced, which Putin has steadily eroded.

"As leader of the USSR, he worked with President (Ronald) Reagan to reduce our two countries' nuclear arsenals ... After decades of brutal political repression, he embraced democratic reforms," Biden said.

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

It took Putin more than 15 hours to publish the text of a condolence telegram in which he said Gorbachev had had a "huge impact on the course of world history" and "deeply understood that reforms were necessary" to tackle the problems of the Soviet Union in the 1980s.

French President Emmanuel Macron called Gorbachev "a man of peace whose choices opened up a path of liberty for Russians".

German ex-chancellor Angela Merkel, who grew up in communist-ruled East Germany, said she had feared that Gorbachev's Moscow would crush an uprising against communist rule in 1989, as it had done elsewhere in eastern Europe in previous decades.

"But... no tanks rolled, no shots were fired."

In response to Russia's invasion of Ukraine, Merkel's successor as chancellor, Olaf Scholz, has abandoned decades of detente to make Germany's foreign and defence stance much bolder.

'DEMOCRACY HAS FAILED'

He said Gorbachev's "perestroika" reforms had made it possible to bring down the Iron Curtain and reunify Germany, adding pointedly:

"He died at a time when not only has democracy in Russia failed ... but also when Russia and Russian President Putin have dug new graves in Europe and begun a terrible war."

While Western news outlets ran lengthy reports, Russian media were far less interested in Gorbachev's passing.

Putin's spokesman Dmitry Peskov told an educational forum that Gorbachev's "romanticism" about rapprochement with West had been misplaced. "The bloodthirstiness of our opponents showed itself," he said.

The Interfax news agency quoted the Kremlin as saying it had not been decided whether Gorbachev would receive a state funeral.

Sergei Naryshkin, director of Russia's Foreign Intelligence Service and one of the "siloviki" or men of power close to Putin, said: "'Perestroika' has long become history, but today we all have to deal with its consequences.

"It fell to Gorbachev to lead the country in a very difficult period, to face many external and internal challenges, for which an adequate response was not found."

WESTERN PARTNERSHIPS

After decades of Cold War tension and confrontation, Gorbachev brought the Soviet Union closer to the West than at any point since World War Two.

But his legacy was finally wrecked as the invasion of Ukraine on Feb. 24 brought Western sanctions crashing down on Moscow, and politicians in both Russia and the West began to speak of a new Cold War - or worse.

"We are all orphans now. But not everyone realises it," said Alexei Venediktov, head of the liberal radio station Ekho Moskvy, which closed down after coming under pressure over its coverage of the Ukraine war.

When pro-democracy protests rocked Soviet-bloc nations in communist Eastern Europe in 1989, Gorbachev refrained from using force, breaking with the legacy of previous Soviet leaders who had sent tanks to crush uprisings in Hungary in 1956 and Czechoslovakia in 1968.

But the chain of largely bloodless revolutions fuelled aspirations for autonomy in the 15 republics of the Soviet Union, which disintegrated over the next two years in chaotic fashion.

Gorbachev - who was briefly deposed in August 1991 by party hardliners attempting a coup - struggled in vain to prevent that collapse.

TURBULENT REFORMS

"The era of Gorbachev is the era of perestroika, the era of hope, the era of our entry into a missile-free world ... but there was one miscalculation: we did not know our country well," said Vladimir Shevchenko, who headed Gorbachev's protocol office when he was Soviet leader.

"Our union fell apart, that was a tragedy and his tragedy," RIA news agency cited him as saying.

On becoming general secretary of the Soviet Communist Party in 1985, aged just 54, Gorbachev had set out to revitalise the system by introducing limited political and economic freedoms, but his reforms spun out of control.

His policy of "glasnost" allowed previously unthinkable criticism of the party and the state, but also emboldened nationalists who began to press for independence in the Baltic republics of Latvia, Lithuania, Estonia and elsewhere.

Many Russians never forgave Gorbachev for the turbulence that his reforms unleashed, considering the subsequent plunge in their living standards too high a price to pay for democracy.

Vladimir Rogov, a Russian-appointed official in a part of Ukraine now occupied by pro-Moscow forces, said Gorbachev had "deliberately led the (Soviet) Union to its demise" and called him a traitor.

Ruslan Grinberg, a liberal economist and friend, told the news outlet Zvezda after visiting Gorbachev in hospital: "He gave us all freedom - but we don't know what to do with it."