Harford County School Superintendent Jacqueline C. Haas has notified students and parents that all field trips to Washington, Philadelphia and New York City have been canceled until further notice because of the risk of war.
In a letter to parents, Haas said that other field trips outside the county would be evaluated on a case-by-case basis.
Schools have been reminded that anyone entering buildings must display a photo identification badge, employee identification or visitors badge.
Vendors going into school buildings or offices must show company identification.
Parents picking up their children also will be asked to show photo identification.