The US has announced plans to send forces to Saudi Arabia in the wake of attacks against the country’s oil infrastructure.
Secretary of Defence Mark Esper told reporters the deployment would be “defensive in nature”. Total troop numbers have not yet been decided.
Yemen’s Iran-backed Houthi rebels have said they were behind the attacks against two oil facilities last week.
But the US and Saudi Arabia have both blamed Iran itself.
Earlier on Friday, President Trump announced new sanctions against Iran while signalling he wanted to avoid military conflict.
“I think the strong person approach, and the thing that does show strength, would be showing a little bit of restraint,” he told reporters in the Oval Office.
The fresh sanctions, which Mr Trump described as “highest level”, will focus on Iran’s central bank and its sovereign wealth fund.
Saudi Arabia and the United Arab Emirates requested assistance, Mr Esper said.
He said the US forces would focus on boosting air and missile defences and would “accelerate the delivery of military equipment” to both nations.
Chairman of Joint Chiefs of Staff Gen Joseph Dunford called the deployment “moderate” and said it would not number in the thousands. He gave no further details about the type of forces that would be sent.
According to The New York Times, when reporters asked Mr Esper if military strikes on Iran were still being considered, the defence secretary responded: “That’s not where we are right now.”
Strikes hit the Abqaiq oil facility and the Khurais oil field in Saudi Arabia a week ago, affecting the global oil supply.
On Wednesday, the kingdom’s defence ministry showed off what it said were the remains of drones and cruise missiles proving Iranian involvement. The country was still “working to know exactly the launch point”, a spokesman said.