As new U.S.-led naval patrols in the Persian Gulf raise the stakes with Iran and Tehran's nuclear deal collapses, the ongoing tensions have drawn renewed attention to foreign military bases in the region.
Here's a look at the presence of the U.S. and others in the region:
The U.S. has stationed some 14,000 troops in Afghanistan supporting America's longest war. Some 8,000 others come from NATO forces.
The U.S. Navy's 5th Fleet, which oversees the region, is based in Bahrain, an island nation off the coast of Saudi Arabia that is home to over 7,000 American troops. Sheikh Isa Air Base on the island also hosts American fighter jets, surveillance aircraft and a U.S. special forces operations center. The U.S. considers the island a "major non-NATO ally." Britain, meanwhile, has just opened its first military base east of the Suez Canal since 1971 in Bahrain.
The U.S. has some 5,000 troops in Iraq in the aftermath of the war against the Islamic State group.
The tiny, oil-rich nation hosts over 13,000 American troops and the U.S. Army Central's forward headquarters. It also maintains forces and equipment at two air bases and a naval base in the country. Kuwait International Airport also hosts the U.S. military's largest regional air logistics point. Some 2,200 American mine-resistant tactical vehicles are stationed there. The U.S. also considers Kuwait a "major non-NATO ally."
A few hundred U.S. military personnel are based in Oman. The sultanate also allows U.S. military overflights and port visits. It also allows the U.S. to preposition munitions in the country. America signed a new port access agreement with Oman this year. Britain has signed a deal to build a new naval base in the country.
The forward headquarters of the U.S. military's Central Command is at Qatar's sprawling Al Udeid Air Base, home to up to 13,000 American troops. Qatar plans to further expand the base, which saw the U.S. position nuclear-capable B-52 bombers there as tensions rose with Iran. Turkey also has its own military base in the country, to the chagrin of Saudi Arabia, which sees Ankara as a regional rival for influence.
The U.S. pulled troops out of Saudi Arabia in the wake of the Sept. 11 terror attacks and the 2003 invasion of Iraq. Al-Qaida leader Osama bin Laden long criticized the presence of American forces there. This summer, U.S. officials said fighter aircraft, air defense missiles and likely more than 500 American troops would return to Riyadh's Prince Sultan Air Base over tensions with Iran. U.S. special operations troops also reportedly have assisted Saudi forces along its border with war-torn Yemen.
UNITED ARAB EMIRATES
Dubai's Jebel Ali port in the United Arab Emirates is the largest port of call for the U.S. Navy outside of America. The UAE hosts 5,000 U.S. military personnel, many at Abu Dhabi's Al Dhafra Air Base, where American drones and advanced F-35 jetfighters are stationed. The U.S. Navy also maintains a small base in Fujairah on the Gulf of Oman. France also maintains its own navy base in Abu Dhabi, the Emirati capital.