The Pentagon has announced it will deploy additional US troops and missile defence equipment to Saudi Arabia and the United Arab Emirates.
The announcement comes as President Donald Trump has put off any immediate military strike on Iran in response to the attack on the Saudi oil industry.
Defence Secretary Mark Esper told Pentagon reporters this is a first step to beef up security and he would not rule out additional moves in the future.
General Joseph Dunford, chairman of the Joint Chiefs of Staff, said more details about the deployment will be determined in the coming days, but it would not involve thousands of US troops.
Other officials said the US deployment would likely be in the hundreds and the defensive equipment heading to the Middle East would probably include Patriot missile batteries and possibly enhanced radars.
The announcement reflected Mr Trump’s comments earlier in the day when he told reporters that showing restraint “shows far more strength” than launching military strikes and he wanted to avoid an all-out war with Iran.
Instead, he laid out new sanctions on the Iranian central bank and said the easiest thing to do would be to launch military strikes.
“I think the strong person’s approach and the thing that does show strength would be showing a little bit of restraint,” Mr Trump told reporters during a meeting with Australian Prime Minister Scott Morrison.
Mr Dunford told reporters the extra equipment and troops would give the Saudis a better chance of defending against unconventional aerial attacks.
“No single system is going to be able to defend against a threat like that,” he said, “but a layered system of defensive capabilities would mitigate the risk of swarms of drones or other attacks that may come from Iran.”
The US has not provided any hard evidence that Iran was responsible for the attacks, while insisting the investigation continues, but Mr Esper said the drones and cruise missiles used in the attack were produced by Iran.
“The attack on September 14 against Saudi Arabian oil facilities represents a dramatic escalation of Iranian aggression,” Mr Esper said, adding that the US has thus far shown “great restraint”.
In deciding against an immediate US strike, Mr Trump for the second time in recent months pulled back from a major military action against Iran that many Pentagon and other advisers fear could trigger a new Middle East war.
In June, after Iran shot down an American surveillance drone, Mr Trump initially endorsed a retaliatory military strike then abruptly called it off because he said it would have killed dozens of Iranians.
On Friday, he left the door open for a later military response, saying people thought he would attack Iran “within two seconds” but he has “plenty of time”.