PORTLAND, Ore. -- Extra security was on hand - and an after-school event was canceled - at a Northeast Portland elementary school after social media posts about racist flyers raised concerns.

Portland Public Schools spokesman Dave Northfield said many of the social media rumors regarding King Elementary School were not true.

He said the one rumor that was true was a racist letter sent to an organizer of the annual multicultural festival, Good in the Hood, earlier this week. Northfield said the organizer has an office in a building connected to King Elementary School.

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“That led to a lot of rumors though that police did check out, or security checked out throughout the day, and unfortunately did cause a lot of stress to the community. None of those rumors turned out to be true,” Northfield said.

Among the false rumors were that students were being handed racist letters on campus and graffiti had been sprayed on school walls.

The hysteria caused the cancellation of an end-of-year carnival celebration that was scheduled on campus shortly after the school day was over.

In addition to the racist letter sent to Good in the Hood organizers, the concerns come after a Southeast Portland middle school student was the target of racial slurs at nearby bus stop on Thursday.

More: Racist verbal attack aimed at Portland student prompts school security increase

Northfield advised that unusual behavior at Portland Public Schools should be reported to police and school district officials.