It is not just the Saudi king who will be skipping the Camp David summit of US and allied Arab leaders. Most Gulf heads of state won't be there.
The absences will put a damper on talks that are designed to reassure key Arab allies, and almost certainly reflect dissatisfaction among leaders of the six-member Gulf Cooperation Council with Washington's handling of Iran and what they expect to get out of the meeting.
Saudi Foreign Minister Adel al-Jubeir announced late on Sunday that newly installed King Salman will not be attending. The ostensible reason was because the upcoming summit on Thursday coincides with a humanitarian cease-fire in the conflict in Yemen, where a Saudi-led coalition is fighting Shiite rebels known as Houthis.
Crown Prince Mohammed bin Nayef, who is also interior minister, will lead the Saudi delegation and the king's son, Deputy Crown Prince Mohammed bin Salman, who is defense minister, will also attend.
President Barack Obama had planned to meet King Salman one-on-one a day before the gathering of leaders at the presidential retreat but the White House did not take his decision to skip the summit as a sign of any substantial disagreement with the United States.
The king, who took power in January after his brother King Abdullah died, has not traveled abroad since his ascension to the throne.
The tiny island kingdom of Bahrain said separately that its delegation would be headed by the country's crown prince, Salman bin Hamad Al Khalifa.
Bahrain, whose leadership has close ties to the Saudis, is an important military ally of the US. It is the longstanding host to the Navy's 5th Fleet, which is responsible for operations around the Arabian Peninsula and northern Indian Ocean, and is Washington's main naval counterbalance to Iran.
At the summit, leaders of Gulf nations will be looking for assurances that they have Obama's support at a time when the region feels under siege from Islamic extremists and by Iran's rising influence. The Gulf states worry the nuclear pact taking shape with the US, Iran and other nations may embolden Tehran to act more aggressively in the region.
Israeli Prime Minister Benjamin Netanyahu has expressed similar concerns, saying the emerging deal will leave too much of Iran's nuclear infrastructure intact while giving it quick relief from economic sanctions.
Netanyahu has been an outspoken critic of the deal, raising tensions with the White House. US attempts to reassure Israel that the deal will have strong safeguards have done little to ease its concerns. Netanyahu has claimed that moderate Sunni Arab countries see "eye to eye" with Israel on the matter, though he has not elaborated.
Abdulkhaleq Abdullah, a professor of political science at Emirates University, said Gulf leaders were staying away from the Camp David gathering to signal their displeasure over the nuclear talks.
"I don't think they have a deep respect, a deep trust for Obama and his promises. There is a fundamental difference between his vision of post-nuclear-deal Iran and their vision," he said. "They think Iran is a destabilizing force and will remain so, probably even more, if the sanctions are lifted. ... They're just not seeing things eye to eye."
The sultan of Oman, Qaboos bin Said, is among those staying away. The sultanate will be represented instead by the deputy prime minister, Sayyid Fahd bin Mahmoud Al Said, and other officials, the country's official news agency announced.
The sultan's absence comes as little surprise. The long-serving monarch, whose country maintains cordial relations with Iran and has served as a go-between for Tehran and Washington, returned home in March after spending several months in Germany being treated for an undisclosed illness.
Health issues are also expected to keep the president of the United Arab Emirates, Sheikh Khalifa bin Zayed Al Nahyan, from attending. He became ill in January last year and has not been seen publicly since.
Crown Prince Sheik Mohammed bin Zayed Al Nahyan, the president's half-brother, held talks with Obama at the White House last month and is expected to lead the Emirati delegation.
Abdullah, the Emirati professor, said the Gulf ties with the United States remain strong, but they have been strained during Obama's tenure.
He said Obama is seen within the region as impersonal compared to his predecessors. He also noted that recent comments to The New York Times in which Obama warned that dissatisfaction at home was perhaps a bigger threat than Iran came across as unnecessary "lecturing."
"You just pre-empted the whole meeting with this kind of statement," he said.
Among those who will be at the summit is the Kuwaiti emir, Sabah Al Ahmad Al Sabah. He arrived at Andrews Air Force Base on Monday, the official Kuwait News Agency reported.
Also, Qatar's emir, Sheikh Tamim bin Hamad Al Thani, is scheduled to depart Monday to take part in the meeting.