Defence Secretary Lloyd Austin sought on Saturday to reassure allies in the Middle East that President Joe Biden's administration was committed to the region despite Washington increasingly turning its attention towards countering China.
It was unclear how much impact Austin's speech would have with allies in the Middle East, since it is not backed by any announcements of further deployments or new weapon sales in the region.
Gulf Arab states, heavily reliant on the US military umbrella; have expressed uncertainty about Mr Biden's focus on the region, especially after the US withdrawal from Afghanistan.
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They are closely watching efforts to revive a global-powers nuclear pact with Iran.
"Let's be clear: America's commitment to security in the Middle East is strong and sure," Mr Austin said in a speech in Bahrain during a trip to Gulf.
Mr Austin said there needs to be more multilateral and integrated operations in the region with allies.
He added that the US was committed to countering Iran, even as Washington works to revive the 2015 nuclear deal.
"We remain committed to a diplomatic outcome of the nuclear issue. But if Iran isn't willing to engage seriously, then we will look at all the options necessary to keep the United States secure," Mr Austin said.
Gulf Arab states have asked to be included in the negotiations, and for any deal to address what they call Iran's ballistic missile programme and destabilising behaviour in the region.