Below, AFP examines some of the major concentrations of US forces in the region, which fall under the US military's Central Command (CENTCOM).

- Bahrain -

The tiny Gulf kingdom hosts an installation known as Naval Support Activity Bahrain, where the US Navy's Fifth Fleet and US Naval Forces Central Command headquarters are based.

Bahrain's deep-water port can accommodate the largest US military vessels, such as aircraft carriers, and the US Navy has used the base in the country since 1948, when the facility was operated by Britain's Royal Navy.

Several US ships have their home port in Bahrain, including anti-mine vessels and logistical support ships.

- Iraq -

The United States has troops in Iraq's autonomous Kurdish region as part of the international coalition against the Islamic State group, but their mission is due to end by September under a deal between Washington and Baghdad.

American forces have already completed their withdrawal from facilities in federal Iraq -- whose government is a close ally of Iran, but also a strategic partner of Washington -- under the same agreement.

US forces in Iraq and Syria were repeatedly targeted by pro-Iran militants following the outbreak of the Gaza war in October 2023, but responded with heavy strikes on Tehran-linked targets, and the attacks largely subsided.

- Kuwait -

Kuwait has several US bases, including Camp Arifjan, the location of the forward headquarters for the US Army component of CENTCOM. The US Army also has stocks of equipment and supplies in the country.

Ali al-Salem Air Base hosts the 386th Air Expeditionary Wing, which the military describes as the "primary airlift hub and gateway for delivering combat power to joint and coalition forces" in the region. Additionally, the United States has drones including MQ-9 Reapers in Kuwait.

- Qatar -

Al Udeid Air Base in Qatar includes the forward components of CENTCOM, as well the command's air forces and special operations forces.

It also hosts rotating combat aircraft, and the 379th Air Expeditionary Wing, which the military says includes "airlift, aerial refueling intelligence, surveillance, and reconnaissance, and aeromedical evacuation assets."

Iran fired missiles at Al Udeid last June following US strikes targeting Iranian nuclear facilities.

- Syria -

The United States for years maintained troops in Syria as part of international efforts against the Islamic State group, which rose out of the country's civil war to overrun large parts of that country and neighboring Iraq.

US forces are currently in the process of withdrawing from Syria, and three sources told AFP earlier this week that the American exit would be completed within a month.

- United Arab Emirates -

Al Dhafra Air Base in the UAE hosts the US 380th Air Expeditionary Wing, a force that is composed of 10 squadrons of aircraft and also includes drones such as MQ-9 Reapers.

Combat aircraft have rotated through Al Dhafra, which also hosts the US Air Forces' hub for "advanced air warfare training."