Mikhail Gorbachev said Tuesday that he was proud of his role in the fall of the Berlin Wall 20 years ago, defending himself against Russian critics who accuse him of losing the Soviet empire.

- I am proud that we -- and by that I mean both Western and Eastern European countries -- found an approach that took everyone's interests into account, so this most painful thing was liquidated - Gorbachev said.

Gorbachev indicated that leaders had no choice other than ending the division of Germany into Communist East and NATO-aligned West.

- The issue is not shame, but the fact there was a split in a country in the centre of Europe, the centre of the world, with a huge population - he told reporters in Moscow.

Gorbachev, 78, is widely admired in the West but often criticised in Russia for policies that led to economic chaos and the dismantling of Moscow's sprawling empire.

He has been praised for his decision not to use force to stop the mounting resistance to Communist regimes in eastern Europe in the late 1980s, which culminated in the dramatic fall of the Berlin Wall on November 9, 1989.

The fall of the barrier, where many East Germans had been killed trying to flee to the West, paved the way for Germany's reunification in 1990.

- If the Soviet Union had wanted, it could have stopped reunification. And what would have happened then? I don't know. Maybe World War III - Gorbachev mused in a free-wheeling talk with a group of reporters.

Gorbachev also criticised the behaviour of the United States, which he said had suffered from a "victor's complex" in the years after the Cold War, overextending its power throughout Europe and the world.

- The Americans should understand that their monopoly has ended - Gorbachev said earlier, speaking at the presentation of a book by US billionaire and former media mogul Ted Turner at his foundation in Moscow.

- But that America is going to be a leader for a long time, that it is going to be very influential -- this is a fact, whether you like it or not. -

Gorbachev praised US President Barack Obama, who has sought to improve the United States' image in the world and repair US-Russian relations that were damaged under his predecessor George W. Bush.

Comparing Obama's efforts with his own attempt to reform the Soviet Union in the 1980s, which was called "perestroika", or "restructuring", Gorbachev said that Obama faced the harder task.

- I do not envy Obama, because I think changing and 'restructuring' America is not easier than changing the Soviet Union - Gorbachev said.

- I wish the Americans luck. I think the president's steps need the support of the American people - he added.