RIYADH • Saudi Arabia's King Salman approved hosting US forces in the country to boost regional security and stability, the state news agency SPA reported on Friday.
The US Defence Department confirmed the move in a statement, saying it would deploy troops and resources to Saudi Arabia to "provide an additional deterrent" in the face of "emergent, credible threats".
The gesture comes amid rising tensions between Washington and Teheran in the Gulf that have impacted global oil markets.
On Friday, Iran said it had seized a British oil tanker in the Strait of Hormuz, but denied Washington's assertion that the US Navy had downed an Iranian drone nearby earlier last week.
The decision on hosting US forces aims "to increase joint cooperation in defence of regional security and stability and to preserve its peace", SPA said, quoting a Ministry of Defence official, without giving further details.
A US official, speaking on condition of anonymity, said the deployment would include about 500 US military personnel in Saudi Arabia, and is part of a boost in the number of US troops in the Middle East that the Pentagon announced last month.
In June, the Pentagon said it would deploy 1,000 troops to the Middle East but did not say where they were going.
Relations between Washington and Teheran worsened last year when US President Donald Trump abandoned a 2015 nuclear deal between world powers and Iran.
Under the pact, Iran agreed to restrict nuclear work, long seen by the West as a cover for developing nuclear weapons, in return for lifting sanctions. But sanctions have since been reimposed, badly hurting Iran's economy.
Mr Trump has said he considers Saudi Arabia an important partner in the Middle East and counterweight to the influence of Iran.
US armsmaker Lockheed Martin was on Friday awarded a US$1.48 billion (S$2 billion) contract to build the Terminal High Altitude Area Defence missile interceptor for Saudi Arabia, bringing the total value of the deal to US$5.36 billion.
The new contract was a modification to a previously awarded agreement to produce the missile defence system for Saudi Arabia, the Pentagon said.