The Gulf Cooperation Council includes Saudi Arabia, Kuwait, Qatar, Bahrain, the United Arab Emirates (UAE) and Oman.

US officials have portrayed the summit as a working meeting rather than a symbolic get-together. But the absence of many top Arab leaders, in addition to King Salman, is viewed as a reflection of frustration with Obama's pursuit of the international nuclear deal with Iran and a perceived US failure to support opposition fighters in Syria.

Obama called Saudi Arabia a critical partner in the fight against Islamic State and highlighted his interactions with the two leaders who came in King Salman's place.

Crown Prince bin Nayef said his country attached great importance to the "strategic and historic relationship" with Washington.

Obama did not have private meetings on his public schedule with the leaders from the other countries. They arrived at the White House later on Wednesday evening for a dinner with the president.