John Kerry was on Monday holding talks with his counterparts from six Gulf monarchies on the war in Syria and Iran's disputed atomic programme, on his first visit to the Gulf as US secretary of state.
Kerry, who flew in to the Saudi capital late on Sunday after a two-day trip to Cairo, kicked off with an early morning meeting with the foreign ministers of Bahrain and Kuwait, an AFP correspondent said.
He was later to hold bilateral talks with the foreign ministers of the other four monarchies making up the Gulf Cooperation Council (GCC) -- Saudi Arabia, the United Arab Emirates, Oman and Qatar, officials said.
A US State Department official told reporters that Kerry would also hold talks in Riyadh with Palestinian president Mahmud Abbas, with a lunch meeting planned.
The GCC ministers met among themselves on Sunday and issued a joint statement pledging their support for a negotiated settlement in Syria based on an offer of talks by Syrian opposition chief Ahmed Moaz al-Khatib.
They also demanded a binding UN Security Council resolution "that would set a clear mechanism and time framework for the talks".
The ministers urged the Security Council "to decide, based on the seventh chapter, to protect civilians and end bloodshed, preserve Syria's unity and its stability and achieve the Syrian people's legitimate demands."
They also demanded "helping Syrians defend themselves... against the regime's brutal assault."
Several oil-rich monarchies of the GCC, including Saudi Arabia and Qatar, have supported the rebellion inside Syria against President Bashar al-Assad's regime, a staunch ally of their regional arch-foe Iran.
The six ministers opened their Sunday meeting with criticism against world inaction on Syria and Iranian "interference" in their internal affairs.
"The Syrian crisis has become more of a quasi-catastrophe through the unjustified killing of the Syrian people," Bahraini Foreign Minister Sheikh Khaled al-Khalifa said at Sunday opening session.
Sheikh Khaled criticised "the international community's lack of serious and rapid action" towards resolving the two-year conflict which the United Nations says has killed more than 70,000 people.
In a news conference after the Sunday meeting, Sheikh Khaled said: "We thank Kerry for America's commitment with regard to the security of the region and we will share our concerns about the relationship with Iran and the developments in Syria."
After winding up the Saudi leg of his tour later Monday, Kerry will head to Abu Dhabi and later to Qatar.