At least two persons were shot at the University of Missouri as bomb and other threats in several schools and universities across the United States send security personnel scrambling with students and parents.
The two persons, who were shot in Missouri, were taken to a hospital, says a report.
The Virginia Tech campus, which witnessed a gunman killing 32 people before shooting himself on Monday, saw another bomb scare on Wednesday in the building housing the president's office but it turned out to be false alarm.
Similar false bomb threats were reported form University of California's Hastings Law college in San Francisco and from University of Minnesota where eight buildings were evacuated.
In New Jersey, a school was closed after someone left a message on the answering machine of the principal, saying he was coming to school with a gun to kill the students. Police locked in students and searched their bags.
Media reports said in Lawrenceville in New Jersey, a student was arrested after he waved an air gun from dormitory window. It was not a real gun but police were not taking any chances.
Reports of similar incidents leading to locking down of educational institutions were coming in from across the country till late into the evening.