This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Razor blades and ammunition were found on a school playground in Phelan on Monday morning, the latest in a series of  incidents that have taken place on or around campus within the past week, officials said.

Baldy Mesa Elementary School personnel discovered the ammunition and razor blades while students were arriving to the campus, located in the10300 block of  Baldy Mesa Road, according to a statement from the Snowline Joint Unified School District.

The district’s police department called the Victor Valley Sheriff’s Station to alert them of the threat, noting that ammunition and razor blades were among the items found the playground, the San Bernardino County Sheriff’s Department said in a news release.

Students who were already at school for the day were secured into the multipurpose room while parents were notified, according to officials.

Gate A was closed until further notice.

The school was already on inclement weather schedule for Monday, and the statement said parents were welcome to keep their children home for the day or pick them up if they were already at school.

No additional information was provided about Monday’s incident.

Monday’s incident marked the third in a week involving a possible weapon or ammunition, according to the school district.

On May 13, a knife was found on campus with a “threatening letter” taped to its blade, the district said. A specific student or staff member was not named in the threat.

The following day, staff were notified of pistol ammunition found on Bonanza Road right in front of the school, according to the Snowline JUSD Police Department.

A school police officer recovered live pistol rounds, which were found to be degraded and corroded upon further examination. The ammunition was believed to have been manufactured between 1940 and 1946.

It may have been tossed out of the window of a vehicle driving eastbound on Bonanza near Baldy Mesa Road, police added.

There was no known connection between any of the incidents, all of which are under investigation.

Anyone with information can submit a tip through the WeTip hotline by calling 1-800-78-CRIME, or by going to the website www.wetip.com.