DUBAI, United Arab Emirates — The president of the United Arab Emirates, who helped forge a federation from seven backwater Gulf states and built it into a high-tech commercial crossroads of gleaming skyscrapers, has died. He was 86.

Sheik Zayed bin Sultan Al Nahyan, listed by U.S.-based Forbes magazine as among the richest rulers in the world, has been absolute ruler of the United Arab Emirates, the world's ninth largest oil producer, for more than 30 years. He had been ailing for several years and did not attend Arab summits. He had a kidney transplant in August 2000.

His eldest son, Sheik Khalifa bin Zayed Al Nahyan, has been heir apparent since his father named him in 1969 crown prince of Abu Dhabi, the capital and richest of the seven emirates.

Emirates officials, speaking on condition of anonymity, said the Emirates constitution provides for UAE prime minister and vice-president, Sheik Maktoum bin Rashid Al Maktoum, who is a close relative of Sheik Zayed, to become acting president. A successor will be appointed within 30 days.

Abu Dhabi TV interrupted regular broadcasting to break the news of Sheik Zayed's death, but no cause of death was provided. The announcement was followed by an Islamic cleric appearing on TV reading verses from the Qur'an.

The official Emirates news agency, WAM, announced news of his death, saying: "The presidential court announces to the people of the Emirates, the Arab and Muslim worlds, and the entire world, that the leader of the nation and the builder of its civilization, His Highness Sheik Zayed bin Sultan Al Nahyan, died on the evening of Tuesday, Nov. 2, the 19th of Ramadan. May God have mercy on him.''

Under Sheik Zayed's rule, the Emirates became a leading oil producer and financial and banking centre with close ties to the United States and other western nations. But following the Sept. 11, 2001, attacks on the United States, the Emirates were among several Middle Eastern countries that came under pressure from Washington to reform its financial and banking sectors, which had been linked to the funnelling of funds to international terrorist groups, like al-Qaida.

Sheik Zayed died a day after announcing the Emirates' first cabinet reshuffle since 1977. The reshuffle, which WAM said was suggested by Sheik Maktoum, saw another of Sheik Zayed's 21 sons, Sheik Saif bin Zayed Al Nahyan, named interior minister.

The reshuffle also saw a new oil minister appointed plus the appointment of the Emirates' first woman cabinet minister, with Sheika Lubna Al Qasimi being named economy minister.

With Sheik Zayed's ailing health keeping him out of the public spotlight during the past few years, Sheik Maktoum has become the public face of the Emirates, building close ties with the West and Arab neighbours and presiding over the wealthy country's continuing growth, spurred by growth in the financial, technological and construction sectors.

Following his father's death, Sheik Khalifa is expected to automatically become ruler of Abu Dhabi, and his half-brother, Sheik Mohammed bin Zayed Al Nahyan, will likely be the next crown prince of the emirate.

Based on Islamic tradition, Sheik Zayed will be buried as soon as possible, most likely on Wednesday. It was unlikely that the burial would be delayed to wait for heads of state to arrive.

While the rulers of the seven emirates must choose the next president, they are expected to settle on Sheik Khalifa. Although lacking his father's charisma and reputation, Sheik Khalifa is a powerful figure in the country, holding the post of deputy commander of the armed forces and, as chairman of Abu Dhabi's executive council, handling most of the emirate's day-to-day affairs.

Condolences poured in from around the region for the popular leader, who invested billions of oil dollars to transform Abu Dhabi from a dusty desert outpost into an oasis of highrises, parks, fountains, manicured flower beds, restaurants and a wildlife island.

"His death is a big loss for the Arab and Islamic nations and to humanity,'' Oman's Foreign Minister Youssef bin Alawi told Dubai-based Al-Arabiya TV.

Kuwait's information minister, Mohammed Abul-Hassan, credited Sheik Zayed with helping Kuwaitis who fled to the Emirates after Iraqi President Saddam Hussein ordered his forces to invade Kuwait in 1990, a move that led to the U.S.-led 1991 Persian Gulf War.

Jordan's royal family, led by King Abdullah, declared a 40-day period of mourning after being informed of the death of Sheik Zayed, a close ally of Jordan credited with depositing hundreds of millions of dollars into Jordan's Central Bank to boost the country's faltering economy.

The Jordanian prime minister's office also declared a three-day mourning period for government offices, over which Jordanian flags will fly at half-mast.

Sheik Zayed ruled Abu Dhabi since 1966, a city which was to become the capital of the United Arab Emirates when the seven-emirate federation was formed in 1971 after taking independence from Britain in a campaign that Sheik Zayed led. The Emirates, located along the southern Gulf shore, is a powerful member of the Organization of Petroleum Exporting Countries. Abu Dhabi controls nearly 80 per cent of the Emirates' total wealth, most of which is derived from oil.

Petroleum was discovered off Abu Dhabi in 1958 and the first oil exports started flowing in 1962. The pace of the area's growth increased in 1971 after the United Arab Emirates was formed, with petroleum being a driving force in the development of the country's other six members.

Sheik Zayed has been married many times, although he adhered to the Muslim code of never having more than four wives at any one time. He was the father of more than 21 sons and an undivulged number of daughters.