DOVER — Five schools throughout the state received threatening phone calls warning of bombs or active shooters Tuesday morning, one week after a rash of nearly identical threats up and down the Delmarva Peninsula.

Police responded to Central Middle School in Dover, Long Neck Elementary School in Millsboro, Woodbridge High School in Greenwood, Silverlake Elementary School in Middletown and Rehoboth Elementary School after automated calls were placed to the schools around 9:30.

Nothing was found at any of the locations and the five schools were given an all-clear within three hours.

Dover Police Department spokesman Master Cpl. Mark Hoffman said the call to Central Middle School warned of shooters on the roof of the building. The school was placed on lockdown.

After the school resource officer contacted Dover police, officers arrived within a minute and began searching the school.

According to Central Middle School, Dover police told school officials at 10:20 the lockdown could end.

Delaware State Police spokesman Master Cpl. Gary Fournier said the caller to Long Neck Elementary School stated he was armed and located on the school roof. The school was placed on lockdown and police responded with a K9 unit and helicopter. Students were moved to the cafeteria and then bused away.

After nothing suspicious was found the area was cleared and students had begun returning by 12:15.

At Silverlake Elementary School the automated call warned of a bomb. Students and teachers were moved to buses and driven away from the school while it was searched.

They later returned after nothing alarming was found.

While no students were at Woodbridge High School, faculty was evacuated until searches located nothing out of the ordinary.

Rehoboth Beach Police also responded to a robo-call bomb threat at Rehoboth Elementary School. Area police were alerted at 9:43 and were aided by state and Dewey Beach police.

The students were moved to a safe location and the building was cleared around 12:15, according to Rehoboth Police Chief Keith Banks.

The incidents follow automated bomb threats placed on Jan. 11 and 12 to at least 11 schools in locations ranging from Ocean City, Maryland to Wilmington.

Capital School District Superintendent Dan Shelton said the threats are a major disruption and have required teachers to temporarily adopt new lessons plans related to the response, such as dealing with stress.

“We should be able to focus on reading, writing and arithmetic,” he said.

Going forward, some lessons may have to be changed slightly or consolidated to ensure teachers can cover key subjects.

The schools have processes for what to do in emergency situations such as Tuesday’s, and while Dr. Shelton could only share general details due to security risks, he said notification of Dover police occurred very quickly.

Sen. Ernie Lopez, R-Lewes, released a statement thanking officials for their responses and pledging the perpetrators will be prosecuted.

“Let me make something perfectly clear to those who continue to try to instill fear into moms and dads, grandparents and our community as a whole: your actions are despicable and when you are discovered you will be prosecuted to the fullest extent of the law,” he said.

“It is only a matter of time until your arrogance and mean-spiritedness catch up with you and when they do, please be mindful of the fact that in choosing to use our children to spread your fear, patience and understanding as to your reasoning will be difficult to bestow,” he continued. “We will find you.”

Authorities request anyone with information contact state or local police.

Dover Police Department can be reached at 736-7111, and calls to state police can be made to Troop 2 Youth Aid Division at 834-2620, Troop 3 Youth Aid Division at 697-4454 or Troop 4 Youth Aid Division at 856-5850. Information may also be provided by calling Delaware Crime Stoppers at 1-800-TIP-3333, going to www.delaware.crimestoppersweb.com or sending an anonymous tip by text to 274637 (CRIMES) using the keyword “DSP.”