The United States and Qatar are preparing for a possible Iranian attack, one that may come in retaliation for a possible U.S. military mission, which President Donald Trump has publicly threatened.

The U.S. military’s largest base in the Middle East, al-Udeid Air Base in Qatar, which houses roughly 10,000 troops, has begun moving out some personnel due to the anticipated Iranian response, according to the New York Times. It was also the target of Iran’s telegraphed retaliation after U.S. forces carried out strikes on three of its nuclear facilities last year.