By Roberta Rampton
RIYADH (Reuters) - U.S. President Barack Obama met Saudi Arabia's King Salman on Wednesday to seek joint action on security threats including Iran and Islamic State, but his visit is overshadowed by Gulf Arab exasperation with his approach to the region.
The American president has come to the world's top oil exporter for a fourth and likely last time, hoping to reassure Salman and other Gulf leaders, whom he will meet on Thursday, of Washington's commitment to their security.
Most of the Gulf Arab monarchies have in private been sorely disappointed by Obama's presidency, regarding it as a period in which the United States has pulled back from the region, giving more space to their arch rival Iran to expand its influence.
For his part, Obama has spoken of his desire to persuade Gulf states to arrive at a "cold peace" with Iran that would douse sectarian tensions and allow all sides to focus on what he sees as a greater threat emanating from Islamic State.
After a low-key arrival in Riyadh, which unlike some previous visits was not shown live on Saudi television, Obama met Salman and a group of top princes and officials at the Erga palace for a two-hour meeting.
U.S. Defense Secretary Ashton Carter, National Security Adviser Susan Rice and Central Intelligence Agency Director John Brennan were among Obama's entourage, demonstrating the focus on security in the president's agenda with his Gulf counterparts.
On Thursday, he will attend a summit of the Gulf Cooperation Council (GCC), a group of monarchies comprising Saudi Arabia, Kuwait, Qatar, Bahrain, the United Arab Emirates and Oman.
Apart from Oman, they are ruled by Sunni Muslim dynasties who see revolutionary, Shi'ite Iran as a threat to their security and say its involvement in Iraq, Syria, Lebanon and Yemen has fuelled conflict and deepened sectarian divisions.
That tension surfaced again on Wednesday when Iran's Supreme Leader Ayatollah Ali Khamanei attacked Riyadh's attempts to isolate its ally, Lebanon's Hezbollah movement, in a series of fiery Tweets.
"Hezbollah is shining in the Muslim world. It doesn't matter if a corrupt, dependent and hollow government with the use of petrodollars condemns it in a statement. To hell with it," he wrote.
The White House shares the view of Gulf Arab states that Tehran plays a destabilising role, but its push for the nuclear deal Iran agreed with world powers last year caused fears in Riyadh that Washington was not listening to their concerns.
There was no immediate word on whether Obama or Salman had addressed a New York Times report that Saudi Arabia has threatened to sell its multi-billion dollar U.S. assets if Congress passed a bill that could hold the kingdom responsible for any role in al Qaeda's Sept. 11, 2001 attacks.
Obama said he opposes the bill because it could expose the United States to lawsuits from citizens of other countries.
The attack was mounted by al Qaeda, then based in Afghanistan. Fifteen of the 19 hijackers were Saudi nationals, although no U.S. investigation to date has reported finding evidence of Saudi government support for the attacks.
Before Obama met King Salman, in an ornate room in a Riyadh palace, U.S. Defense Secretary Ash Carter had talks with his Gulf Arab counterparts on ways of countering Iranian influence and fighting the Islamic State group.
They agreed on joint cooperation towards improving Gulf missile defence, special forces and maritime security, but no new deals were announced.
The GCC secretary general said the bloc and the United States would stage joint maritime patrols to stop weapons smuggling to Iran. American officials said these were already taking place and did not represent a new step.
Obama's words of reassurance follow a series of top-level meetings between U.S. and Gulf officials in recent years in which Washington aimed to get across the same message.
He and Salman last met in the United States in September, a meeting that followed a Camp David summit with Gulf leaders in May that several of the monarchs did not attend.
More recently, Obama was quoted in a U.S. magazine interview describing some Gulf and European states as "free riders" who called for U.S. action without doing enough themselves.
In comments that were widely criticised in the Gulf but not directly responded to by top officials, he was also quoted as answering a question about whether Saudi Arabia was America's friend by saying "it's complicated".
Saudi television earlier broadcast Gulf rulers being welcomed on the runway by King Salman and a host of other robed officials, scenes that were widely contrasted by Saudi social media users with the lack of pomp on Obama's arrival.
Obama is set to meet with the leaders of Britain, France and Italy in Hanover on Monday with Islamic State and other security issues high on the agenda.
(Additional reporting by Yeganeh Torbati; Writing by Angus McDowall; Editing by William Maclean and Dominic Evans)