A middle school in Beaverton, a city in the U.S. State of Oregon, has been declared on lockdown following an email threat received Friday afternoon, Oregon police said.

Police officers from the Washington County Sheriff's Office (WCSO) of Oregon have arrived at Stoller Middle School in the Beaverton School District, the third largest school district in the state, and urged parents of the students to stay clear of the campus.

"The school went into lockdown due to an email threat received. Please do not go to the school at this time. Law enforcement is on scene and we will update you as soon as we have more information," the authorities of the Beaverton School District tweeted.

"Multiple deputies are onscene at Stoller Middle School to ensure the safety of all students and staff. Investigators are working closely with the @BeavertonSD to gather more information," WCSO Oregon said in a tweeted post.

Details of the email threat were not disclosed so far.

The police said no suspicious persons or objects have been located inside the school, and there are no reports of injuries.