The new restrictions on the man who until last week was next in line to the throne and ran the kingdom’s powerful internal security services sought to limit any potential opposition for the new crown prince, Mohammed bin Salman, 31, the officials said, speaking on the condition of anonymity so as not to jeopardize relationships with Saudi royals.
It was unclear how long the restrictions would remain in place. An adviser to the Saudi royal court referred queries to the Information Ministry, whose officials could not immediately be reached for comment on Wednesday. A senior official in the Saudi Foreign Ministry reached by telephone on Wednesday night described the account as “baseless and false.”
The Saudi monarch, King Salman, shook up the line of succession last week with a string of royal decrees that promoted his favorite son, Mohammed bin Salman, to crown prince and removed Mohammed bin Nayef, 57, from the line of succession.
The elder prince was also replaced as interior minister by a 33-year-old nephew, marking the end of a career that had won him deep respect in Washington and other foreign capitals for his work dismantling Al Qaeda’s networks inside the kingdom after a string of deadly bombings a decade ago.
Supporters of Mohammed bin Salman, often referred to as M.B.S., have lauded his promotion, saying it empowered a young, ambitious prince who has laid out a positive vision for the kingdom’s future.
But his elevation effectively ended the political prospects of many older princes, some of whom consider him rash, power hungry and inexperienced. Prince Mohammed also serves as the kingdom’s defense minister, putting him in charge of Saudi Arabia’s costly military intervention against the Houthi rebels in neighboring Yemen.
Saudi state news media has gone out of its way to portray a smooth transition, repeatedly broadcasting a video showing Mohammed bin Salman deferentially kissing the hand of Mohammed bin Nayef, often referred to as M.B.N., who wishes him well.
But the restrictions placed on the elder prince suggest fear that some members of the sprawling royal family are upset with the change, and that public appearances by him could exacerbate such sentiments.
“It’s an indication that M.B.S. does not want any opposition,” a senior United States official said. “He doesn’t want any rear-guard action within the family. He wants a straight elevation without any dissent — not that M.B.N. was plotting anything anyway.”
The official said the United States government was in contact with the Saudi Interior Ministry, but that American officials had not had any formal contact with Mohammed bin Nayef and were monitoring the situation closely.
“M.B.N. has been such a great friend and partner of the U.S., we would not want to see him treated inelegantly or indecorously,” the senior American official said.
Mohammed bin Salman dined with Mr. Trump at the White House in March. That cleared the way for Mr. Trump’s visit to Saudi Arabia, where he declared the Saudis key allies in combating terrorism and extremism.
The restrictions have also been imposed on Mohammed bin Nayef’s daughters, according to a former American official who maintains ties to Saudi royals. A married daughter was told that her husband and their child could leave their home while she had to stay, the former official said.
One Saudi close to the royal family said the new restrictions had been imposed almost immediately after Mohammed bin Salman’s promotion.
After the announcement, Mohammed bin Nayef returned to his palace in Jidda to find that his trusted guards had been replaced by guards loyal to Mohammed bin Salman, according to the Saudi and a former American official. Since then, he has been prevented from leaving the palace.
Another former American official with close contacts with the royal family confirmed that Mohammed bin Nayef had been barred from leaving the kingdom, but said he had not heard that he had been restricted to his palace.
The promotion of Mohammed bin Salman last week followed his meteoric rise from near obscurity since his father came to the throne in early 2015 to the summit of Saudi power. Since then, he has been put in charge of the Defense Ministry, given oversight of the state oil monopoly and spearheaded the development of a plan called Saudi Vision 2030 that seeks to reduce the kingdom’s dependence on oil, diversify the economy and loosen some social restrictions.
His rise came at the expense of Mohammed bin Nayef, who has maintained a low profile while developing strong relationships with successive American administrations and intelligence officials.
During Mohammed bin Salman’s rise, American officials had struggled to build relationships with both princes while trying not to be used as leverage in any rivalry between them.
Mohammed bin Salman’s elevation has been accompanied by that of a number of other young princes. One of his brothers, Khalid bin Salman, was recently named the ambassador to Washington. He is believed to be in his late 20s.
Mohammed bin Nayef was replaced as interior minister by a nephew, Abdulaziz bin Saud bin Nayef, who has no clear experience in law enforcement or intelligence matters. In a unique arrangement in a country traditionally guided by deference to elders, he is the son of Saud bin Nayef, the governor of the Eastern Province, effectively making the young prince his father’s boss.