The U.S. Department of State has strengthened its security warnings for American citizens in the Middle East, citing a complex security environment and the possibility of sudden and unexpected escalation in the coming period.

In an advisory issued early Sunday, the department urged Americans across the region to remain highly vigilant and prepare for potential emergencies that could include sudden flight cancellations, suspension of air services, or the closure of airspace.

The State Department also called on Americans outside the Middle East to reconsider travel plans to or through the region, warning that recent military tensions and exchanges of missile attacks could increase risks to U.S. interests and facilities, including diplomatic and commercial sites.