Tributes to former US President George HW Bush have poured in from around the world, as global leaders honoured him for his role in helping to end the Cold War and reduce the danger of nuclear annihilation.
Australian Prime Minister said a message of condolence was forwarded to President Trump "expressing our country's sincere sympathy both to the American people, as well as to the Bush family".
"President Bush was a great friend of Australia," he said, speaking on the sidelines of the G20 summit.
"And he was a great friend of democracy, and he was a great friend of freedom. And he advocated and fought for these things all of his life. From his time of service to his country, and to freedom in World War Two, all the way through his public life."
Bush, the 41st US president, also routed President Saddam Hussein's Iraqi army in the 1991 Gulf War but lost his chance for a second term in the White House after breaking a no-new-taxes pledge.
The last leader of the Soviet Union Mikhail Gorbachev, with whom Bush signed a strategic arms reduction treaty, said many of his memories were linked with the former US president.
"We happened to work together in years of great changes. It was a dramatic time demanding huge responsibility from everyone," Russia's Interfax news agency cited Gorbachev as saying on Saturday.
'A very fine man'
Speaking in Buenos Aires, US President Donald Trump said Bush was "a high quality man" who led an "exemplary" life.
"He was a very fine man. I met him on numerous occasions. He was just a high quality man who truly loved his family," Trump told reporters at a G20 summit.
In Houston, people left flowers at iron gates leading to the street of Bush Sr's home and at a bronze statue of him in a city park.
Bush's death on Friday night at age 94 was announced by longtime spokesman Jim McGrath.
No further details about the circumstances of his death were immediately available.
The White House said a state funeral is being arranged at the National Cathedral in Washington.
Day of mourning declared
The president, who plans to attend the funeral with first lady Melania Trump, also designated a national day of mourning on Wednesday, December 5, and ordered the lowering of the American flag for 30 days.
Former presidents including Jimmy Carter remembered Bush as a leader of grace and humility.
"His administration was marked by grace, civility and social conscience," Carter said in a statement.
Barack Obama described Bush as "a patriot and humble servant" while Bill Clinton, who defeated Bush in the 1992 presidential election, recalled his "great long life of service, love and friendship".
Bush was the father of former president George W Bush, who served two terms in the 2000s, and former Florida Governor Jeb Bush, who unsuccessfully sought the 2016 Republican nomination for president.
Like his sons, Bush was a Republican.
His death came seven months after that of his wife, former first lady Barbara Bush, to whom he was married for 73 years.
A messages sits among flowers left at the base of a statue of George H.W. Bush outside the George H.W. Bush Presidential Library and Museum. Source: AAP
"The entire Bush family is deeply grateful for 41's life and love, for the compassion of those who have cared and prayed for Dad, and for the condolences of our friends and fellow citizens," George W Bush said in a statement.
A US naval aviator during World War II, the elder Bush also served as vice president for eight years during Ronald Reagan's two terms as president.
British Prime Minister Theresa May said Bush Sr's ethos of public service was the guiding thread of his life and "an example to us all".
