Reform of the Soviet Union and the Communist Party should have begun earlier, ex-Soviet President Mikhail Gorbachev told Reuters in an interview at the Frankfurt Book Fair.

Mr Gorbachev, the last leader of the Soviet Union before its collapse in 1991, said he was right to have pushed the country towards more freedom and democracy but said he would do many other things differently if he had his time again.

"A lot," he answered when asked what he would change if he could. "We waited, we delayed too long to reform the party and we clung to the USSR," he said after presenting his collected works at the world's biggest book fair.

"The union should have been reformed earlier."

Mr Gorbachev resigned at the end of 1991 after surviving a coup by hardliners that left him considerably weakened, but not before he had made "perestroika" and "glasnost" internationally recognised words for reform and openness.

He tried to preserve the Soviet Union in some form, but declarations of independence from its various republics forced his hand and the union was dissolved the day after he resigned. Answering questions from an audience at the book fair, Mr Gorbachev praised former US Presidents Ronald Reagan and George H.W. Bush, who together with Mr Gorbachev made the first moves towards disarmament that would end the Cold War.

"It was amazing, when I was first told about President Reagan, he was a man on the extreme right of the Republican Party," he said. "At the end, he left the office of president as a peacemaker."

"George Bush was perhaps the best partner of all: wise, knowledgeable, careful," he said of the former Central Intelligence Agency director.

For Boris Yeltsin, who gained much support during the 1991 coup and was the first leader of post-Soviet Russia, Mr Gorbachev had little praise.

"I don't want to speak ill of the dead but I don't have any reason to speak well of him," he told Reuters. "I knew he had an ungovernable character. He wanted to be the hero at any price."

But ,he said the Soviet nomenklatura - the elite in key positions of power - more responsible than Mr Yeltsin himself for events that took place under Mr Yeltsin's leadership. He did not elaborate.

Asked whether his public image was an accurate reflection of his character, Mr Gorbachev, who is still deeply unpopular with many Russians, said: "There are people who think I'm a demi-god. Others think I'm a traitor." "There are no happy reformers," he added. "But I have to consider myself lucky that I had a chance to make a difference."

The book fair comes to an end tomorrow.