King Fahd bin Abdul Aziz of Saudi Arabia, whose strategic alliance with the United States prompted a far-reaching backlash by Islamic radicals, died Monday and was succeeded by his half brother, Crown Prince Abdullah, in a swift and scripted transition that signaled policy continuity in the world's largest oil exporter.

The death of Fahd brought the first change in the Saudi throne in 23 years. The ascendance of Abdullah, believed to be 82 -- and like Fahd, a son of the kingdom's founder, Abdul Aziz ibn Saud -- brought the country a step closer to a transition to a younger generation, some of whose members are less wedded to the religious establishment and more eager to see the kind of reforms that Fahd and Abdullah only tentatively embraced over the past 15 years.

Such a shift, analysts say, may become evident in jockeying over powerful posts that are vacant, such as intelligence chief, or might soon open in the Defense Ministry and National Guard.

For now, at least, the succession is more a formality than the end of an era. Ever since Fahd suffered a stroke in 1995, Abdullah had effectively ruled, steering key policies and serving as the kingdom's public face.

Despite rumors of squabbles and rifts over the pace of economic and political change, the royal family appears to have reached consensus years ago on both Abdullah's accession and that of his eventual successor, to help assure at least the veneer of calm in a deeply conservative country that prizes stability.

As the kingdom readied for Fahd's burial Tuesday, with state television broadcasting Koranic recitation and foreign leaders preparing to arrive, that was the thrust of sentiments: Abdullah needed to do little to reshape policy that was already his.

Fahd, who was believed to be 84, had entered a hospital in Riyadh on May 27 with acute pneumonia. He died about 6 a.m. Monday. Hours later, Saudi television interrupted regular broadcasting to announce his death.

"With all sorrow and sadness, the royal court in the name of His Highness Crown Prince Abdullah bin Abdul Aziz and all members of the family announces the death of the custodian of the two holy mosques, King Fahd bin Abdul Aziz," said the country's information minister, Iyad bin Amin Madani, reading a statement on state television.

The statement said the royal family had chosen Abdullah as Fahd's successor and Prince Sultan, the country's defense minister, as the new crown prince. "We were absolutely, pleasantly surprised that it took minutes, not even hours" to put in place the succession, said Mahmoud Ghamdi, the Riyadh bureau chief for the Saudi Gazette. Since Fahd's illness, "the crown prince has pretty much taken over, and people have gotten used to Crown Prince Abdullah being in charge of things. Things look sad, but things look terribly smooth."

There was no word on who would become the second deputy prime minister, effectively the number three position in the kingdom, surprising some people in Riyadh, the capital.

The White House was informed of Fahd's death about 2:30 a.m. Washington time. President Bush called Abdullah and expressed condolences over the death and congratulations on his accession, and U.S. officials said they expected little change in Saudi policy. The White House said a U.S. delegation would travel to Saudi Arabia for the burial, although Bush will not attend.

A Pivotal State

In line with the traditions of Saudi Arabia's conservative brand of Islam, there will be no state funeral. Prayers will be held Tuesday afternoon at the Mosque of Imam Turki bin Abdullah, the main mosque in Riyadh.

Neighboring Arab countries declared periods of mourning, and the Arab League postponed a summit scheduled for Wednesday in the Egyptian resort of Sharm el-Sheikh, site of a series of bombings on July 23.

Many Arab leaders who were due to attend the summit will instead go to Riyadh to pay respects to Fahd, whose country's oil wealth and importance to Islam as the site of its most sacred shrines make it perhaps the region's pivotal state.

On news of his death, crude oil prices soared past $61, the highest level in weeks.

Abdullah is generally well regarded in the kingdom, more popular than his powerful brothers. Many people view him as a principled nationalist who is willing to undertake reform but is constrained by his relatives.

On inheriting the throne, Abdullah continues to face many of the issues that have marked his de facto leadership. Like Fahd, who became king in 1982 during a surge in oil prices, Abdullah has enjoyed growing oil revenue that has helped offset, at least temporarily, longer-term concerns over unemployment and how to rehabilitate the nation's aging infrastructure.

For the past two years, Saudi security forces have battled Islamic radicals within the country -- a sensitive issue for a government that justifies its rule by a centuries-old pact between the royal family and the conservative religious establishment. Attacks began in the mid-1990s, but three suicide bombings of Western residential compounds in Riyadh in May 2003 drove home the potential force of a campaign claimed by al Qaeda with the aim of toppling the royal family and driving foreigners from the kingdom.

The government has reported successes: It says it has killed or captured 23 of the 26 men it included on a most-wanted list published last year. In a gun battle on April 21, three reputed radicals were killed on the outskirts of Mecca.

Conciliation and Repression

Abdullah also faces turmoil in neighboring Iraq and the prospect of a nuclear Iran across the Persian Gulf. At times, he has been buffeted by calls for reform and appeals from deeply traditional religious figures that he go only so far. Like Fahd, he has faced those demands with a mix of conciliation and repression. Partial municipal elections in Saudi areas this year gave new influence to religious conservatives, while three prominent liberal activists were jailed in May.

As in many Arab countries, steps toward reform risk being perceived as American-dictated.

"Those people who expect Abdullah to make a dramatic change, especially on the internal front, they are wrong. Abdullah is also extremely worried about the stability of the country," said Ramzi Khouri, a consultant for the Okaz Media Group. "He and the others will try to keep a balance between what the government believes is right and what the Saudi street believes is right."

Many analysts expect Abdullah to move slowly to consolidate the rest of his power, as well. For decades, consensus has distinguished decision-making within the family, and the new king is not likely to diverge.

Early on, for instance, Abdullah was seen as less enamored of the Saudi alliance with the United States, but has earnestly sought to mend it, in line with Fahd's policy, especially after the reverberations that followed the disclosure that 15 of the 19 men who carried out the Sept. 11, 2001, attacks were Saudi citizens.

Some analysts predicted that his first major decisions will be to fill vacancies. The second deputy prime ministership, second in line to the throne, was not announced Monday, although many people expect it will be Prince Nayef, the interior minister, who is viewed as a conservative even within the royal family. Another powerful brother is Prince Salman, the governor of Riyadh, seen by some as more encouraging of reform.

Another top job to fill is the intelligence position, made vacant after its ailing director stepped down this year. For months, Prince Saud bin Fahd bin Abdul Aziz, a son of the late king, has overseen its activities.

With Sultan becoming crown prince, he may resign as defense minister, opening that job. Similarly, Abdullah may give up his post as commander of the National Guard. Several analysts said they were waiting to see the fate of Prince Bandar bin Sultan, the longtime U.S. ambassador who stepped down last month.

Part of that transition may make way for the grandsons of Abdul Aziz, who founded the kingdom in 1932. Unlike his sons, who received only rudimentary education before the onset of tremendous oil wealth, the younger generation is viewed as somewhat savvier and more tolerant of reform. Sons of both Abdullah and Sultan have emerged as forceful players, with independent reputations.

Fahd's Legacy

For the past decade, Fahd, the fourth son of Abdul Aziz to rule, receded from political life. He used a wheelchair and was seldom seen in public. He occasionally led cabinet meetings, but rarely spoke. His long autumn overshadowed the vigor of his early years as king, when he presided over a strengthening alliance with the United States in the 1980s, the cornerstone of his foreign policy.

After the onetime playboy ascended to the throne in June 1982, he poured billions into Saudi infrastructure, modernizing a country that was a backwater just half a century earlier. The revenue and Saudi Arabia's role as a swing producer -- able to guide global oil prices given its vast reserves -- cemented its position as one of the world's strategic economic powers.

The wealth helped Saudi Arabia spread its fiercely conservative brand of Islam throughout the Muslim world. It also enabled the kingdom's support for Afghan guerrillas fighting Soviet troops in Afghanistan and for Iraq in its eight-year war with Iran, whose Islamic revolution was deemed a threat.

The war ended in 1988, to Iraq's advantage. Two years later, Iraq invaded Kuwait, prompting the decision that may prove one of Fahd's most important legacies. He invited 500,000 U.S. and other foreign troops into the country, the birthplace of Islam and home to Islam's most sacred shrines.

The move outraged conservative Muslims in Saudi Arabia and abroad and helped ignite the campaign by Osama bin Laden, then a wealthy and popular Saudi veteran of the Afghan war, to overthrow the family's rule.

Several months after the 1991 Persian Gulf War, hundreds of Islamic scholars wrote to Fahd seeking curbs on the royal family's power and a reversal of its pro-Western policies. Fahd introduced limited reform, appointing a 60-member advisory council to help rule the country. It now numbers 150 with expanded power, but remains handpicked by the royal family.

Although the royal family agreed that Crown Prince Abdullah would become king, rivalries may yet emerge regarding the line of succession. Story, A9.A man passes a shop in Riyadh with posters of, from right, Saudi Arabia's founding king, Abdul Aziz ibn Saud; King Fahd; Crown Prince Abdullah, who became king yesterday; and the new crown prince, Sultan.