On the military front, the United States is pursuing discussions with regional defense ministers to discuss the expansion of bases and overflight rights so that the United States and other nations can expand the intensity and scope of airstrikes against ISIS in Iraq and Syria.

The senior State Department official said that Mr. Kerry planned to discuss with the Saudis “in some detail” plans to train and equip moderate Syria rebels.

Saudi Arabia and other Sunni states have their interests, as well, including a more assertive effort to oust President Bashar al-Assad.