US President Barack Obama (L) speaks with King Salman bin Abdulaziz al-Saud of Saudi Arabia at Erga Palace in Riyadh, on April 20, 2016
Riyadh (AFP) - President Barack Obama held talks with Saudi Arabia's King Salman on Wednesday as he began a two-day visit hoping to ease tensions with the historic US ally.
Riyadh and its Sunni Arab Gulf neighbours have bristled at what they see as Washington's tilt towards their regional rival Shiite Iran after Tehran's landmark nuclear deal with world powers.
Obama, making probably his last visit to Riyadh as president, attends a summit of Gulf leaders on Thursday hoping to focus on intensifying the fight against the Islamic State group and resolving the wars in Syria and Yemen.
King Salman, 80, greeted the arriving Gulf leaders at a central Riyadh airbase but was not present when Obama landed at King Khalid International Airport in the city's north.
It was a more low-key reception than for Obama's previous trip to the kingdom, after the death of King Abdullah in January 2015.
Then, Salman along with his crown prince and deputy crown prince greeted Obama as a military band played.
After waving and walking down a red carpet on the stairs from Air Force One, he was greeted this time by Prince Faisal bin Abdulaziz, the governor of Riyadh, and Foreign Minister Adel al-Jubeir.
Saudi state news channel Al-Ekhbaria did not broadcast Obama's arrival although it did have live coverage of the Gulf leaders' landing.
"I and the Saudi people are very pleased that you Mr President are visiting us," Salman said at his Erga Palace before a two-hour meeting with Obama, who responded that the United States was "very grateful for your hospitality."
The kingdom's official Saudi Press Agency gave no detail of the talks but said they included "combating terrorism".
Obama was to meet later with Abu Dhabi's Crown Prince Sheikh Mohammed bin Zayed Al-Nahyan to see how to "reinforce cooperation to defeat the Islamic State group", the White House said.
Tensions between Riyadh and Washington have increased sharply due to what Saudi Arabia sees as Obama's disengagement from traditional US allies in the region and opening towards Iran.
- 'Alliance-building' effort -
Though the visit is being touted as an "alliance-building" effort, "it will just as likely highlight how far Washington and Riyadh have drifted apart in the past eight years," Simon Henderson, of the Washington Institute for Near East Policy, wrote in Foreign Policy magazine.
"For Obama, the key issue in the Middle East is the fight against the Islamic State... For the House of Saud, the issue is Iran."
Iran's emergence from international isolation after the nuclear deal has raised deep concerns among Gulf Arab states, who oppose Tehran indirectly in a range of Middle East conflicts.
The weeks before the visit were marked by Saudi outrage over Obama's comments published in the April edition of US magazine The Atlantic.
He said the Saudis needed to "share" the Middle East with their Iranian rivals, because competition between Riyadh and Tehran has helped to feed proxy wars and chaos in Syria, Iraq and Yemen.
Arab News columnist Mohammed Fahad Al-Harthi on Wednesday became the latest Saudi commentator to lament "the United States' disengagement from assisting in resolving the region's problems".
Also clouding the visit is congressional draft legislation that would potentially allow the Saudi government to be sued in US courts over the September 11, 2001 attacks on the United States, in which nearly 3,000 people were killed.
- Cloud cast by 9/11 bill -
Fifteen of the 19 hijackers in the attacks claimed by Al-Qaeda were Saudi citizens. No Saudi complicity has been proven and the kingdom has never been formally implicated.
Obama, making his fourth trip to the kingdom, has stated his opposition to the draft legislation.
Ahead of the visit the White House emphasised the strength of an alliance that has endured more than 70 years.
Despite worries in the Gulf, Washington remains a major weapons supplier and has bases in the region.
Obama will be joined at Thursday's summit of the six-nation Gulf Cooperation Council by Defence Secretary Ashton Carter and Secretary of State John Kerry.
The Pentagon chief in Riyadh on Wednesday pleaded with his Gulf counterparts for greater economic and political involvement in Iraq, which is battling both IS jihadists and an economic crisis.
Saudi Arabia and other Gulf nations are part of a US-led coalition carrying out air strikes against IS in Syria and Iraq, where the Sunni extremists seized swathes of territory.
"I encourage our GCC partners to do more, not only militarily", Carter said after the talks.