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MIDDLETOWN, Del. (CBS) — Schools in the Appoquinimink School District were on lockdown for a brief time on Thursday afternoon following reports of a person with a rifle in the Middletown, Delaware area. However, Middletown High School remains on lockdown after someone threatened to bring a pipe bomb onto the school’s campus, officials say.

Delaware State Police say a man called a bomb threat into the high school around 12:30 p.m. The school went into lockdown immediately.

The school district says police also received a call about an individual with a rifle in the area that prompted all schools to go on lockdown. The lockdown was lifted about an hour later and schools will be dismissed at their normal time.

Middletown High School will do a “staged” dismissal and bring “buses on campus to load in a staggered fashion in order to allow police to provide tight security.”

No injuries were reported.