Preparations are also reportedly underway for a large missile installation from which Patriot surface-to-air missiles can be launched to protect the base from incoming threats.
The moves would likely strengthen the US' controversial relationship with Saudi Arabia, while also responding to rising tensions with Iran which escalated dramatically in recent months.
After the US unilaterally withdrew from a landmark 2015 nuclear deal last year and reimposed tight sanctions, Iran announced in July that it had surpassed limits on enriched uranium imposed in the agreement. The country insists it is not trying to build nuclear weapons.
A standoff has also ensued in the Gulf, with sabotage attacks on foreign tankers, blamed on Iran by the US. In the latest incident Tehran said it had seized a foreign-owned vessel suspected of being used for oil smuggling out of the country/
The Trump administration has long sought to base troops in the remote region, but the decision to send them to Saudi Arabia comes amid outrage over the killing of journalist Jamal Khashoggi. A United Nations report concluded his death at the Saudi embassy in Istanbul was "an extrajudicial execution" sanctioned Crown Prince Mohammed bin Salman.
The Trump administration has also been criticised for its response to the murder.
Despite these issues, the US has said it is committed to helping protect Saudi Arabia from Iranian aggression, and last month said 1,000 troops were being sent to the middle east, but did not say which countries they were going to.
Photographs taken by high-resolution commercial satellites, captured by satellite imagery company Planet Labs, show a deployment of US troops and support personnel who arrived at the air base in mid-June, according to Jeffrey Lewis, director of the East Asia Nonproliferation Project at the Middlebury Institute of International Studies at Monterey, who has studied the new images.
Pictures of the site taken in late June and early July show preparations being made for the arrival of troops, Mr Lewis told CNN.
“A small encampment and construction equipment appeared at the end of a runway by June 27, suggesting that improvements are already underway. The encampment to the east of the runway is typical of Air Force engineering squadrons deployed overseas,” he said.
The US is reportedly hoping to be able to fly stealth, fifth-generation F-22 jets and other fighter planes from the base.
Commander Rebecca Rebarich, a Pentagon spokeswoman, told the New York Times there was “no official announcement” of the deployment to the Middle East but said the American military “continually works to manage our force posture in the region.”
Amid rising tensions between Iran and the US last month, Mr Trump said he was not seeking war with the country but warned, if pushed, the country would face “obliteration like you’ve never seen before”.
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