The U.S. Embassy in Qatar warned American citizens to "shelter in place until further notice." The embassy said in its June 23 alert that it was acting "out of an abundance of caution" but gave no other details. Qatar is home to the Al Udeid Air Base, the largest U.S. air base in the Middle East.

The U.S. Embassy in Qatar told Americans in the country to shelter in place until further notice, without providing a reason, as the region anticipates possible Iranian attacks on American interests in retaliation for U.

The message comes as tensions are high in the Middle East after the U.S. bombed Iranian nuclear sites on Sunday.