Egypt's former vice president Omar Suleiman, veteran spy chief to deposed president Hosni Mubarak, died of a heart attack on Thursday in the United States aged 77, the official MENA news agency reported.
"Former vice president General Omar Suleiman died in the early hours of Thursday in a hospital in the United States," the agency said.
"He was undergoing medical tests in Cleveland," Suleiman's aide Hussein Kamal told AFP, adding that arrangements were being made for the return of his body to Egypt for burial.
MENA quoted an Egyptian diplomat in Washington as saying Suleiman died of a sudden heart attack while undergoing medical tests.
Suleiman had suffered from lung disease for several months, after which he developed heart problems, it reported.
"His health deteriorated suddenly around three weeks ago and he was taken to hospital in Cleveland, Ohio, where he died," the agency said.
Suleiman was appointed vice president during the uprising that toppled Mubarak.
He left Egypt after a failed bid to run in the country's first ever free presidential election in May.
The winner of that election, the Muslim Brotherhood's Mohamed Morsi, sent his condolences to Suleiman's family, his spokesman Yassir Ali said, adding that Suleiman will receive a military funeral, MENA reported.
Suleiman's nomination had infuriated the Muslim Brotherhood, and the Islamist-dominated parliament passed a law to exclude him and other senior former regime figures from standing in the election.
Suleiman was disqualified over faulty paperwork for his candidacy.
After initially travelling to Dubai, he later headed to Germany and then on to the United States for treatment, General Saad al-Abbassi, a member of Suleiman’s presidential campaign team, told AFP.
"His health deteriorated recently. He was in the United States with his family," said Reem Mamdouh, another member of the team.
Suleiman, a pillar of the ousted regime, announced in April that he would stand for the presidency after initially saying he would not.
He was barred from pursuing the country's top job on a technicality, after the election commission said he failed to get endorsements from 15 provinces as stipulated under the law.
Suleiman was widely believed to have formed part of the inner circle of Mubarak, who shortly before his fall named the intelligence supremo vice president.
Born on July 2, 1935 to a well-off family in the southern town of Qena, Suleiman graduated from Cairo's military academy in 1955.
He received military training in the former Soviet Union, and was for years a highly enigmatic figure both to the world at large and at home in Egypt, where the all-powerful military's activities are shrouded in secrecy.
But he increasingly acquired a public face in recent years, being tipped even before the uprising as a potential successor to Mubarak, himself a former head of the air force.
Under Mubarak, Suleiman served as a negotiating partner for the United States, Israel and the Palestinians, orchestrating a series of short-lived truces.
In 1995, Suleiman advised Mubarak to ride in an armoured car during a visit to Addis Ababa that shielded him from the fire of Islamist gunmen who killed the car's driver.
During the 1990s and following the botched assassination attempt in Ethiopia, Suleiman joined the efforts of the CIA and other foreign intelligence agencies to crack down on Islamists at home and abroad.