Guam - Maria Ulloa Elementary School was placed on a modified lockdown just after noon today. The school's principal Patrick Egrubay confirms that a hostile phone call was received threatening one of the school's employees as a result - the gate was locked and monitored and all students and teachers where quarantined to their classrooms to ensure their safety.  Ebgrubay says as a precautionary measure GPD was called and were at the campus to respond to the complaint. Students were released at the end of the school day.