Former US President Ronald Reagan has died at the age of 93 after a long struggle with Alzheimer's disease.
Reagan was president for eight years
He died at home in Los Angeles, where his family were with him.
Current US President George W Bush said Ronald Reagan "won America's respect with his greatness. And won its love with his goodness."
Reagan's White House tenure - from 1981 to 1989 - was marked by the climax of the Cold War and the beginning of the end of Soviet communism.
Tributes have poured in from world leaders current and past.
US President George W Bush said Reagan leaves behind "a nation he restored and a world he helped save".
"May God bless Ronald Reagan," he said.
Former Soviet president Mikhail Gorbachev, who met Reagan on a number of occasions, called him a "great president", thanks to whom the Soviet Union and America had begun a difficult but crucial dialogue.
White House officials said President Bush has ordered flags at US government buildings to be flown at half-mast for the next 30 days.
A representative of the family said Ronald Reagan passed away on Saturday at 1300 (2000GMT) from pneumonia - a complication of Alzheimer's which had afflicted him for a decade.
"We appreciate everyone's prayers over the years," said his wife Nancy, who has cared for him through his illness.
She protected his privacy and had refused to disclose detailed information about the effect his condition had on him.
The couple were married for 52 years.
Reagan revealed in November 1994 that he was suffering from Alzheimer's disease, which destroys brain cells and causes memory loss.
Last month, Mrs Reagan revealed that her husband's illness had got worse.
"Ronnie's long journey has taken him to a distant place where I can no longer reach him," she said.
1911: Born in Tampico, Illinois
1937: Wins Hollywood contract
1966-74: Serves as governor of California
1981-89: Serves as 40th president of the United States
Mar 1981: Survives an assassination attempt
1994: Reveals he has Alzheimer's Disease
Reagan's body will be taken to his presidential library and museum in Simi Valley, California and then flown to Washington for a state funeral. His body will then return to California for burial near his library.
Reagan was the 40th president of the US, taking office at the age of 69, the oldest to do so. He lived longer than any US president.
Before entering politics he had a career in Hollywood films, but never made it big. He described himself as the Errol Flynn of the B-movies.
'Humour and humanity'
Among the many tributes, ex-UK prime minister Margaret Thatcher spoke warmly of the man many regarded as her ideological soulmate during the Cold War years.
"President Reagan was one of my closest political and dearest
personal friends," she said.
She credited him with having "won the Cold War for liberty... without a shot being fired."
"To have achieved so much against so many odds and with such humour and humanity made Ronald Reagan a truly great American hero."
Former US President George Bush Senior remembered Reagan's public speaking skills, describing his "many speeches that could just muster the best in us as a country".