Bomb threats phoned in to 30 schools in five states are being traced to California.

The calls targeted schools in Delaware, Iowa, Massachusetts, Maryland and New Jersey. They reported receiving the calls earlier today. The threats forced evacuations, lockdowns or caused classes to be suspended.

There were 26 schools threatened in New Jersey, and they were given the all-clear after being searched. A New Jersey sheriff said the threats were made in a robotic voice. He said the calls came from numbers generated by a computer and traced to Bakersfield, California.

Students were dismissed from a school outside of Boston, and Delaware police were investigating threats at three schools.