The agency confirmed a report in The Wall Street Journal that said Saudi Arabia would see the greatest reduction in US military support, while Kuwait, Iraq and Jordan would also be impacted.
It said the US plans to pull a Terminal High Altitude Area Defense (THAAD) system, jet fighter squadrons and accelerate the withdrawal of US troops from the kingdom, in addition to the withdrawal of the anti-missile batteries.
The decision reflects both Washington's repositioning of US forces to counter Russia and China as well as shifting sands in the Middle East.
As the curtain draws on the war in Afghanistan, competition with world powers is seen by US officials as the key driver of future military operations. For nearly two decades of the global war on terror, counterinsurgency dominated.
In those two decades and even beginning under the Obama administration which sought a "pivot to Asia," the rise of China has presented myriad challenges as it is now America's main rival in national security terms.
The Biden administration is also hopeful of a more manageable relationship with Russia.
Ideally, defense and national security officials would spend less time concerned with cyberattacks and Russian troop buildups.
However, US President Joe Biden made clear in his meeting with Russian President Vladimir Putin in Geneva this week that those issues persist.