World leaders have praised Boris Yeltsin as a courageous fighter during the Soviet Union's dramatic change that marked the end of the Cold War, and they recalled his colourful, if sometimes volatile, personality.
"President Yeltsin was a historic figure who served his country during a period of momentous change," US President George W Bush said in a statement, shortly after learning of Yeltsin's death on Monday from heart failure.
"He played a key role as the Soviet Union dissolved, helped lay the foundations of freedom in Russia and became the first democratically elected leader in that country's history."
There was no immediate word on whom the US government would send to attend Yeltsin's funeral, which the Kremlin said would be held on Wednesday.
"Although we would sometimes have massive divergences over our politics, we were both, nevertheless, trying to do what we thought best for our country and its people," Mikhail Gorbachev, whose reforms prepared the way for Yeltsin's political rise, wrote in a personal letter to Yeltsin's widow, Naina.
He called Yeltsin's passing a "loss that cannot be replaced."
US Secretary of State Condoleezza Rice, whose academic career was largely spent studying the Soviet Union, said Yeltsin "ushered in a new era for his country in which ordinary Russians were able to speak and worship without fear, to own property, and to choose their leaders freely.
"In doing so, he inspired a generation of young Russians to build a bright new future for their country and to choose peaceful relations with their new neighbors," she said in a statement.
Others hailed Yeltsin as a healer of the Cold War divide, opening up Russia to the rest of Europe.
Yeltsin "will be remembered for the critical role he played in advancing political and economic reforms in Russia, as well as in fostering rapprochement between East and West," UN Secretary-General Ban Ki-moon said, according to a spokeswoman.
Nobel Peace Prize laureate and former Polish President Lech Walesa said it was Yeltsin, not Gorbachov, who was the driving force that ultimately led to the dismantling of the Soviet Union.
"If he hadn't done that, all the processes across the world of that sort would have come to a halt and been drawn back, and so the great service of Yeltsin is what we have today -- a free world, the era based on knowledge, the internet, globalisation. And so we bow our heads in his memory," said Walesa.
"Boris Yeltsin was a large personality in Russian and international politics, a courageous fighter for democracy and freedom and a true friend of Germany," German Chancellor Angela Merkel said.
"Fate gave him a tough time in which to govern, but history will be kind to him because he was courageous and steadfast on the big issues -- peace, freedom, and progress," former US President Bill Clinton and Democratic presidential candidate Hillary Clinton said in a statement.