Saudi Arabia has said it is happy with President Obama's assurances that the recent nuclear deal with Iran will not imperil the Gulf states.

Saudi Foreign Minister Adel al-Jubeir said his country was satisfied that the deal would contribute to security and stability in the Middle East.

He was speaking after King Salman held talks with Obama in Washington,

It is King Salman's first trip to the United States since assuming the throne in January.

The foreign minister said he hoped Iran would use the windfall from the lifting of sanctions for its own development rather than engage in what he termed as "nefarious activities in the region".

"The president explained and affirmed that the agreement prevents Iran from acquiring a nuclear weapon, has a robust and unprecedented inspections regime that includes inspections of all sites... and that has provision for snap back of sanctions should Iran violate the terms of their agreement," he added.

Gulf states fear that lifting sanctions could allow Iran to extend its support for militant groups and actions across the region they consider destabilising.

The Saudi foreign minister also said assurances had been given to President Obama that efforts would be made to relieve the humanitarian situation in Yemen.

Gulf Arab states have sought help to counter the threat of Iranian ballistic missiles. Photo: AFP

The US has backed a Saudi-led coalition's attempts to restore the government in Yemen, in its campaign against Houthi rebels.

Human rights activists and humanitarian organisations have criticised Obama's decision to support the 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.

Obama pressed King Salman to ensure humanitarian organisations were given unrestricted access to Yemen, where the Saudis are leading a coalition against the Houthi rebel movement.

"We share concerns about Yemen and the need to restore a function government that is inclusive and that can relieve the humanitarian situation there," Obama said after the meeting.

'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 arms agreement that would provide weapons for the Saudi military for the campaign against the jihadist group Islamic State and the Houthi rebel movement in Yemen.

The deal primarily comprised missiles for US-made F-15 fighter jets, the officials said.