Fresh from the latest round of Iran nuclear negotiations, U.S. Secretary of State John Kerry is heading to Saudi Arabia to ease Gulf Arab concerns about an emerging deal and discuss ways to calm instability in troubled Yemen.

Kerry flies later Wednesday to Riyadh where he will meet the new Saudi king and the foreign ministers of Bahrain, Kuwait, Oman, Qatar and the United Arab Emirates. The Sunni-ruled Gulf states are unnerved by Shiite Iran's increasing assertiveness in the region. U.S. officials say Kerry will reassure them that any deal with Tehran will not mean American complacence on broader security matters.

The situation in Yemen, where Shiite rebels recently toppled the government, will also be a major topic. The officials say Kerry will reiterate that the U.S. supports political transition.