About 40,000 US troops are stationed in bases in the Middle East and the Persian Gulf region. And Iran has declared US bases as "legitimate targets". In which countries are the most important ones located? A quick overview:
Bahrain
Bahrain is home to the US Navy's Fifth Fleet and the headquarters of the US Navy in the region. Bahrain's deep-sea port is suitable for even the largest US warships, including aircraft carriers.
The US Navy has been using the base since 1948, when it was still operated by the British Royal Navy.
Iraq
The Iraqi government is an ally of Iran, but also a strategic partner of the United States. American troops are stationed in Iraq at numerous military facilities, especially at the Al-Assad and Erbil air bases. In total, there are about 2,500 American troops in the country - as part of the international coalition against the "Islamic State" (IS).
Since the start of the Gaza war, American targets in Iraq and Syria have been repeatedly attacked by pro-Iranian militants. The US has responded with counterattacks, but since then the attacks have largely decreased.
Kuwait
Kuwait is home to several US bases. The US military also maintains a major military equipment storage facility in the country, and Ali al-Salem Air Base serves as an air hub for deploying troops in the region.
Qatar
Al Udeid Air Base on the outskirts of the Qatari capital Doha is one of the most important US bases in the Middle East. It is usually home to around 10,000 troops and civilian personnel. The base is also the command center for the US military in the region. Special forces are also stationed here.
Syria
As part of the fight against ISIS, the US military has maintained several sites in Syria over the years. In April, the Pentagon announced plans to halve the number of troops in the country to fewer than 1,000.
United Arab Emirates
Al Dhafra Air Force Base is home to an air force unit with ten squadrons of aircraft and drones. The base also houses an air and missile defense training center.