The US is planning to deploy a large number of forces to Saudi Arabia to help bolster its defences following an attack on its oil facilities.
The planned deployment will include fighter squadrons, one air expeditionary wing and air defense personnel, the Pentagon said.
The Pentagon, which along with Saudi Arabia blames Iran for the attacks on the oil facilities, said it was sending two additional Patriot batteries and an anti-ballistic missile defense system.
It is unclear how many troops are expected to be sent although sources claim it could be "thousands".
Pentagon spokesman Jonathan Hoffman said: "Taken together with other deployments, this constitutes an additional 3,000 forces that have been extended or authorized within the last month."
It was unclear whether some of the newly announced troops might replace other American forces expected to depart the region in the coming weeks or months.
The Pentagon has yet to announce if it will replace the aircraft carrier USS Abraham Lincoln and its strike group when it eventually wraps up its deployment to the Middle East.
The deployment is part of a series of what the United States has described as defensive moves following the attack on Saudi Arabia's oil facilities last month, which rattled global energy markets and exposed major gaps in Saudi Arabia's air defenses.
Iran has responded to previous U.S. troop deployments this year with apprehension. It denies responsibility for the attack on Saudi Arabia as well as attacks on oil tankers earlier this year.
