US President George W Bush has paid tribute to former President Gerald Ford, who has died at the age of 93.
Gerald Ford served as president for more than two years
Speaking from his ranch in Crawford, Texas, Mr Bush remembered President Ford as a "gentleman who reflected the best in America's character".
Mr Ford was never elected president but took office after Richard Nixon quit over the Watergate scandal in 1974.
He served for two years but lost to Jimmy Carter in 1976, a year after the US accepted defeat in the Vietnam War.
In a televised address, Mr Bush said Americans "came to know President Ford as a man of complete integrity".
"For a nation that needed healing... Gerald Ford came along when we needed him most," he said.
Mr Bush said Mr Ford "stepped into the presidency without ever having sought the office" and helped restore confidence in the White House.
The US flag will be flown at half-mast outside the White House and other government and military buildings for the next 30 days.
Although official plans have yet to be announced, Mr Ford's body is expected to lie in state before funeral services are held in Washington and in Michigan, where he grew up.
Mr Bush's words of praise were echoed by Vice-President Dick Cheney, who was at one time Gerald Ford's chief-of-staff.
Mr Cheney said Mr Ford gave the country the strength, wisdom and good judgement it needed as it faced its greatest constitutional crisis since the civil war.
In Michigan, a makeshift shrine formed outside the Gerald R Ford Museum as a steady stream of people lit candles and laid flowers and flags.
The museum, in the town of Grand Rapids, opened books of condolence for visitors to sign.
Officials at Buckingham Palace in London said the Union flag would fly at half-mast on Thursday, adding that the Queen was sending a personal message to Mrs Ford and President Bush.
People placed flags and flowers outside the Gerald R Ford Museum
Gerald Ford lived with his wife Betty, 88, at Rancho Mirage, about 130 miles (210km) east of Los Angeles in southern California.
A statement from Betty Ford said: "My family joins me in sharing the difficult news that Gerald Ford, our beloved husband, father, grandfather and great-grandfather, has passed away at 93 years of age."
The statement did not give the cause of death.
The former president had suffered ill health this year and was taken to hospital four times for tests and angioplasty. He suffered a stroke in 2000.
Last month he became the longest-living US president when he reached 93 years and 122 days, passing the record held by President Ronald Reagan.
Gerald Ford - born in Omaha, Nebraska - was the only US president never to win a national election.
He was chosen as Richard Nixon's vice-president in 1973, when Spiro Agnew resigned amid corruption charges.
Mr Ford then succeeded to the top job when Nixon resigned over Watergate - the scandal over a break-in at the offices of the rival Democratic party in Washington in 1972.
Ford succeeded Nixon and brought honesty to the White House
On taking office, Mr Ford declared the "national nightmare" of the Nixon scandal over - but soon after revived the debate by controversially granting his former boss a pardon for any crimes committed as president.
Analysts believe in the short term it may have cost him the 1976 election, although in the long term the gesture may have helped heal the country.
Mr Ford was in office as the US accepted its defeat in the Vietnam War, with the fall of Saigon in April 1975.
He was praised for his openness, sunny disposition and, most importantly, his honesty.
Meanwhile, his wife Betty became a national figure in her own right, crusading against drug and alcohol addiction.
After several years out of the public eye because of illness, Mr Ford joined Jimmy Carter, George Bush Senior and Bill Clinton at a memorial shortly after the 11 September 2001 attacks.
He was also at Ronald Reagan's funeral in June 2004.