DUBAI, United Arab Emirates -- The United Arab Emirates' long-ailing ruler and president, Sheikh Khalifa bin Zayed Al Nahyan, died Friday, the government announced in a brief statement. He was 73.
Khalifa oversaw much of the country's economic growth and his name was immortalized on the world's tallest building, the Burj Khalifa, after bailing out Dubai during its financial crisis over a decade ago.
However, after suffering a stroke and undergoing emergency surgery in 2014, a decade after becoming president, he ceased having any involvement in the day-to-day affairs of ruling the country.
The last several years of his life saw his half brother, Abu Dhabi Crown Prince Mohammed bin Zayed, rise to become the de facto ruler and decision-maker of major foreign policy decisions.
The UAE announced a 40-day period of mourning and a three-day suspension of work across the government and private sector, including flags to be flown at half-staff.
There was no immediate announcement on a successor.
Messages of condolences also poured in from around the region and the world.
"The UAE has lost a loyal son, and the leader of its blessed empowerment journey," Sheikh Mohammed bin Zayed wrote on Twitter after his brother's death was officially announced on state media. "Khalifa bin Zayed, my brother, supporter and mentor, may Allah Almighty grant you eternal peace."
In a statement, U.S. Secretary of State Anthony Blinken described Khalifa "as a true friend of the United States," adding that the U.S. remains committed to its steadfast friendship and cooperation with the UAE. Vice President Kamala Harris also expressed her condolences.
Khalifa was born in 1948 in Al Ain, near the border of Oman. He was the eldest son of Sheikh Zayed bin Sultan Al Nahyan, who's revered by Emiratis as the country's founding father. He was trained at Sandhurst -- the royal military academy in England.
In 1969, Khalifa was named as Abu Dhabi prime minister and chairman of the emirate's Department of Defense, which later became the core of the UAE's armed forces.
Khalifa helped boost the UAE's regional profile by bulking up its military with hefty purchases from U.S. weapons manufacturers.
He set warplanes to the NATO-led mission against Moammar Gadhafi's regime in Libya in 2011. In 2014, the Emirates became one of the most prominent Arab participants in U.S.-led airstrikes against the militant Islamic State group in Syria.
Under Khalifa's presidency, the UAE joined Saudi Arabia in sending forces to Bahrain to quell an uprising there by the country's majority Shiite population demanding greater rights from the island-nation's Sunni leadership.
He increasingly used Abu Dhabi's oil wealth to attract cultural and academic centers, such as a branch of the Louvre Museum and satellite campuses of New York University and the Sorbonne. He also presided over efforts to move the OPEC country beyond its reliance on petrodollars with investments in renewable energy research.
He has been credited with overseeing the creation and growth of the Abu Dhabi Investment Authority, now one of the world's largest sovereign wealth funds with close to $700 billion in assets, according to estimates by the Sovereign Wealth Fund Institute.
Khalifa was believed to be among the world's richest rulers with a personal fortune estimated by Forbes magazine in 2008 at $19 billion. He built a palace in the Seychelles, an island-chain nation in the Indian Ocean, and faced complaints there about causing water pollution from the construction site.
His personal life was not much in the public eye. He was passionate about the traditional sport of falconry and was said to enjoy fishing.
Though he had been out of public sight since his stroke, Khalifa's image graces every hotel lobby and major government office across the country. On occasion, Emirati state media published rare photographs and videos of Khalifa.
He is known to have had eight children -- two sons and six daughters -- with his first wife, Sheikha Shamsa bint Suhail Al Mazrouei. He is also survived by several grandchildren.