WASHINGTON – The White House on Monday defended the importance of a meeting this week between the United States and Arab countries at Camp David after the king of Saudi Arabia backed out at the last minute.

King Salman had officially accepted the White House invitation, but late Friday the U.S. learned that Saudi Arabia planned to send lower-level emissaries instead.

"I know there had been some speculation that this change in travel plans was an attempt to send a message to the United States," White House press secretary Josh Earnest said. "If so, that message was not received, because all the feedback that we've received from the Saudis has been positive."

The king called Obama on Monday "to express his regret at not being able to travel to Washington this week," the White House said late Monday. "The two leaders emphasized the strength of the two countries' partnership, based on their shared interest and commitment to the stability and prosperity of the region, and agreed to continue our close consultations on a wide range of issues."

Still, some say the change in plans was meant to signal displeasure with President Obama over a nuclear deal between six world powers and Iran. Tehran and Riyadh are bitter rivals.

"It certainly doesn't look good," said Simon Henderson, who studies the Gulf countries at the Washington Institute for Near East Policy. "It looks as if they are snubbing and I think they are snubbing."

Obama and representatives of the Gulf Cooperation Council will meet Thursday to discuss a series of issues, including combating the Islamic State in Iraq and the Levant, the troublesome situations in Syria, Iraq and Yemen, and the deal struck by the U.S. and five other nations to limit Iran's nuclear program. They will attend a dinner Wednesday at the White House.

Though the meeting is being billed as a summit — a meeting of top leaders — only two of the six Gulf counties — Qatar and Kuwait — will send their leaders.

Two of the six nations — the United Arab Emirates and Oman — already had been expected to send others in their place because of health reasons. The UAE's Sheikh Khalifa bin Zayed al Nahyan is sending Crown Prince Mohamed bin Zayed, and Oman's Sultan Qaboos bin Said is sending the deputy prime minister.

Separately, Bahrain also said Sunday that it would send its crown prince, Salman bin Hamad Al Khalifa.

"We very much feel we have the right group of people around the table," said Ben Rhodes, the White House deputy national security adviser.