As United States President Donald Trump considers launching an attack on Iran, Tehran has warned of swift retaliation.

If the US attacks, Iranian Defence Minister Aziz Nasirzadeh warned this month, “all US bases are within our reach and we will boldly target them”.

Here are some of the US bases and troop deployments in the region that could participate in such a strike - and face reprisal.

US troops under threat of retaliation

“The harm the US will suffer will definitely be irreparable if they enter this conflict militarily,” Iran’s Supreme Leader, Ayatollah Ali Khamenei, said on social media yesterday.

Tens of thousands of US troops are stationed in the Middle East.

Al-Asad Air Base, an Iraqi installation 240km west of Baghdad that is operated jointly by the Iraqi and US air forces, houses thousands of American troops, the largest US deployment in the country. Iran and its proxies have in recent years attacked it repeatedly.

After the US assassinated top Iranian general Qasem Soleimani in January 2020, Tehran fired 16 missiles at bases hosting US forces in Iraq.

Eleven landed at al-Asad, wounding dozens of US troops and gouging deep craters in an attack that authorities said was intended to kill. Iran also launched missiles at a military base in Irbil, in the semi-autonomous Kurdistan region in northern Iraq, during that attack.

Iranian-backed militias have launched missiles and drones at al-Asad as recently as August.

The Trump Administration said this month that it was reducing the US military presence in Syria from eight bases to one: Tanf, located strategically in southern Syria near the Iraqi and Jordanian borders. Details on the timing are vague.

A January 2024 drone strike on Tower 22, a US outpost in Jordan 20km south of Tanf, killed three American soldiers and injured dozens more, the worst attack on the US military since the 2021 fall of Kabul.

Major US military deployments in the Gulf include Naval Support Activity Bahrain, headquarters of the US 5th Fleet and home to some 8300 American sailors, and the Qatari-owned al-Udeid Air Base, which boasts the largest US contingent in the Middle East.

Al-Udeid, 32km southwest of Doha, is a forward command post for US Central Command and can house more than 10,000 troops.

Other Gulf installations housing US troops include Camp Buehring and Ali al-Salem Air Base in Kuwait, and al-Dhafra Air Base in the United Arab Emirates, home to the Air Force’s 380th Air Expeditionary Wing.

Iranian officials warned the Qataris this week that US bases in the Gulf would be legitimate targets in retaliation for an American attack, according to a European official briefed on the matter.

US embassies and diplomatic compounds in the region could also become targets. The US has evacuated some personnel and family members from missions in Iraq and Israel.

Militants funded by Tehran could also threaten US personnel and interests in the region.

“Operational plans have been established for that purpose,” Abu Ali al-Askari, a security official with the Iranian-backed, Iraqi-based Shia militia Kataib Hezbollah, warned.

“Undoubtedly, American bases throughout the region will become akin to duck-hunting grounds … not to mention the unforeseen surprises that may await its aircraft in the skies.”

Asked about preparations to head off potential Iranian reprisals, the Pentagon press office directed the Washington Post to a statement from Defence Secretary Pete Hegseth announcing the “deployment of additional capabilities” to the Middle East.

“Protecting US forces is our top priority and these deployments are intended to enhance our defensive posture in the region,” Hegseth wrote on X.

“American Forces are maintaining their defensive posture and that has not changed,” Pentagon spokesman Sean Parnell said in a statement, which the Pentagon press office also pointed to.

Air France and KLM cancelled flights in and out of Dubai International Airport yesterday. The Air France press office cited “the security situation in the region”. It did not indicate when flights would resume.

The US could attack from the Indian Ocean, or Missouri

While the US military bases and deployments near Iran could launch attacks themselves, they are likely to play a supporting role for strikes launched from outside the region.

The B-2 Spirit stealth bomber, the only US aircraft the Air Force says is equipped to carry the bunker-busting bombs that would be required to destroy Iran’s underground Fordow nuclear enrichment facility, flies out of Whiteman Air Force Base in Missouri.

B-2 bombers have flown non-stop from Missouri to the Middle East and back, refuelling midair on flights that take more than 30 hours.

Washington deployed at least 30 refuelling aircraft from the continental US to Europe on Monday, according to data from flight-tracking site Flightradar24.

An attack could also be launched from Naval Support Facility Diego Garcia, an installation on a remote Indian Ocean atoll that’s owned by Britain and run jointly by the US and British navies.

B-2 bombers can reach Iran from Diego Garcia in five to six hours, analysts say. The US military has used the atoll to launch strikes on Iraq and Afghanistan.

The Pentagon redirected the aircraft carrier USS Nimitz to the Middle East, defence officials told the US Naval Institute this week, to join the USS Carl Vinson as a second US aircraft carrier in the region.

Susannah George, Alex Horton and Mustafa Salim contributed to this report.