Six New Jersey schools were locked down and searched Friday after bomb and shooting threat hoaxes were made by phone, officials said.

Linden High School; Benjamin Franklin Elementary School, Lawrenceville Elementary School and Lawrenceville Prep in Lawrence; and County Prep High School and McNair Academic High School in Jersey City all received threats just hours apart on Friday.

It is unclear if they are related.

Police swept each school with K9s, and deemed each building to be safe. The school day continued at all six schools.

Linden High School students were forced to shelter-in-place after it received a bomb threat at approximately 8:45 a.m. By 11:15 a.m., the school was declared safe by the Union County Bomb Squad, the county sheriff’s K-9 unit and local law enforcement and first responders, officials said.

“It is unfortunate that our children’s education has to be disrupted by reckless threats like these,” Linden Police Chief David Hart said. “Each of these threats are taken very seriously, and we will use every resource at our disposal to ensure that the person responsible is brought to justice.”

The incident is under investigation, and anyone with information is asked to contact the Linden Police Juvenile Bureau at 908-474-8520.

In Jersey City, two high schools were evacuated after receiving bomb threats around 11 a.m.. Students and faculty from County Prep High School and McNair High School were evacuated to nearby schools until police allowed them to return to the building around 1 p.m., said Maryann Dickar, Jersey City Public Schools chief of staff.

Three schools in the same town in Mercer County were among the schools to receive threats, though further investigation showed the calls were swatting incidents, officials said.

At around 10:35 a.m., an adult male called the main office at Benjamin Franklin Elementary School in Mercer County claiming there were six pipe bombs in the building, Superintendent Ross Kasun said. The school was also immediately evacuated to an alternate location, he said.

Within five minutes, an adult male called Lawrenceville Elementary School claiming he was headed to the school armed with a rifle, Lawrence Township police said. The school was also immediately locked down.

A mile away from the elementary school, Lawrenceville Prep School received a call that bombs were placed on the campus, officials said. The school was evacuated, and Notre Dame High School and St. Ann’s School were locked down.

All other schools in the district were also locked down as a precaution.

It is unclear if the same man called in the three threats.

The schools were evacuated while police swept the school with their K-9 unit before deeming the school safe, he said. Classes were back in session at both elementary schools by 11:50 a.m.

“We took (the threat) seriously, like we always do,” Kasun said, noting all student and staff are safe, and the school day will continue as scheduled.

An investigation revealed the calls were “fraudulent and were classified as swatting incidents,” the Lawrence Township Police Department said in a press release.

The matter is still being investigated, and anyone with information is asked to call Lawrence Detective Sean Kerins at 609-844-7121.

Over the past year, state law enforcement agencies have seen a dramatic rise in hoax threats of violence. The threats are “highly disruptive” and capable of creating dangerous situations for first responders, FBI Assistant Special Agent in Charge Christopher Stangl told reporters in November.

7 Ben Franklin Elementary School on lockdown following bomb threat

Sophie Nieto-Munoz may be reached at snietomunoz@njadvancemedia.com. Follow her at @snietomunoz. Find NJ.com on Facebook.

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