Several schools have been vacated after bomb attack threating phone calls in five states of the United States.
The law enforcement agencies have increased school security after threats.
According to foreign news agency, more than a dozen schools have received bomb attack threatening calls and emails in US States Delaware, Maryland, Pennsylvania, New Jersey and Massachusetts, after which those schools have been vacated immediately.
Nine schools of New Jersey received threatening calls early in the morning, hence four schools have been declared clear after search operation, while search operation in five schools was under way.
A school in Massachusetts and three schools in Delaware received threatening phone calls. Law enforcement agencies have increased the security of those schools.
