The Pentagon has decided to send home the only US Navy aircraft carrier in the Middle East, reducing firepower in the region amid heightened tension with Iran, officials said on Thursday.
The decision, confirmed by defence officials, came out a day after Air Force B-52 bombers flew non-stop from the US to the Arabian Gulf.
It was a show of force that military officials said was intended to deter Iran from attacking US forces or interests.
Sending the USS Nimitz home to the US west coast would seem at odds with the idea that a show of force is needed to deter Iran.
It could reflect a split within the defence establishment on whether Iran is likely to strike in the last days of the Trump administration.
This week, an American military officer said the US had detected signs that Iran had prepared for possible attacks on US or allied targets in Iraq or elsewhere in the region.
This was the reason for sending two B-52 bombers from the US to briefly fly over the Gulf on Wednesday, the officer said.
US President Donald Trump spoke of “chatter” that Iran might strike.
Days after a December 20 rocket attack on the US embassy compound in Baghdad by Iranian-supported militia groups, Mr Trump tweeted that Iran was on notice.
“Some friendly health advice to Iran: If one American is killed, I will hold Iran responsible. Think it over,” he wrote on December 23.
"We hear chatter of additional attacks against Americans in Iraq.”
The US is concerned of attacks to coincide with the January 3 anniversary of the American air strike that killed top Iranian commander Qassem Suleimani.
Iran initially retaliated with a ballistic missile strike on a military base in neighbouring Iraq that caused dozens of brain concussion injuries but no deaths among US troops.
But US officials are concerned that Iran might be planning further retaliation.
Calculations on both sides are further complicated by the political transition in Washington to a Biden administration that may seek new paths to dealing with Iran.
President-elect Joe Biden has said that he hopes to return the US to a 2015 agreement between Tehran and world powers in which Iran agreed to limit its nuclear activities in exchange for the lifting of international sanctions.
The US has maintained a near-continuous aircraft carrier presence in the Arabian Gulf since the USS Abraham Lincoln was sent in May 2019 amid concerns that Iran was considering attacks on US interests in the region.
The US also sent more land-based attack planes and re-established a troop presence in Saudi Arabia.
The Nimitz was sent from the US in April and was due to return before the end of the year.
Its planned return was postponed in early December, partly out of concerns about potential Iranian threats.
More recently it was ordered to provide support off the coast of Somalia for the movement of US forces out of the country.
