King Salman of Saudi Arabia is to meet President Barack Obama in Washington, on his first trip to the United States since assuming the throne in January.
The meeting comes amid a period of strained bilateral relations.
The king is expected to reiterate the concern of Gulf states over the recent deal on Iran’s nuclear programme.
They fear that lifting sanctions could allow Iran to extend its support for militant groups and actions across the region they consider destabilising.
Obama is expected to press King Salman to ensure humanitarian organisations are given unrestricted access to Yemen, where the Saudis are leading a coalition against the Houthi rebel movement.
‘Missile deal’:
US-Saudi ties are said to have been strained by Obama’s unwillingness to take military action against Syria’s President Bashar al-Assad, and his support for a nuclear deal that the Saudis fear will ultimately allow Iran to acquire nuclear weapons.
In May, King Salman skipped a summit of Gulf Arab leaders at Camp David, which was widely interpreted as a snub for the US president.
The Obama administration has vowed to make certain that Iran abides by its commitments under the nuclear deal and to do everything it can to “counter Iran’s destabilising activities” in the Middle East once the country’s estimated $56bn (£37bn) of frozen assets are released.
In an effort to reassure its Gulf allies, the US has been working with them to develop a ballistic missile defence system, provide special operations training, authorise arms transfers, strengthen cyber security, engage in large-scale military exercises, and enhance maritime operations to halt illegal Iranian arms shipments.
“We are determined that our Gulf friends will have the political and military support that they need,” Secretary of State John Kerry said on Wednesday.
Senior administration officials told the New York Times that the Pentagon was finalising a $1bn (£660m) arms agreement that would provide weapons for the Saudi military for the campaign against the jihadist group Islamic State (IS) and the Houthi rebel movement in Yemen.
The deal primarily comprised missiles for US-made F-15 fighter jets, the officials said.
Human rights activists and humanitarian organisations have criticised Obama’s decision to support the Saudi-led coalition air campaign in Yemen, which has killed hundreds of civilians since March, and the naval blockade that has caused severe shortages of food, fuel and medicine.
Jeff Prescott, senior director of the National Security Council, said Mr Obama would stress to King Salman the “urgent need to find a resolution to this crisis”.
