The U.S. Embassy in Qatar warned American citizens to "shelter in place until further notice," as Iran vows to hit back against the U.S. for its strikes on nuclear facilities. The embassy said in its June 23 alert that it was acting "out of an abundance of caution" but gave no other details.

The U.S. embassy in Qatar emailed U.S. citizens in the Gulf country on Monday recommending that they shelter in place until further notice, triggering a slew of messages from various Doha-based institutions to employees and students while Qatar maintained that the situation was stable.