If you hear or see low-flying black helicopters in St. Paul or Minneapolis, police are telling the public not to be alarmed — they’re part of training missions.

“It’s going to be an unusual occurrence, and we don’t want people to overwhelm our 911 center with concerned callers,” said Sgt. William Palmer, Minneapolis police spokesman.

U.S. Special Operations Command has been in the two cities for “routine urban-environment training,” both police departments said in news releases. Portions of the training include St. Paul police.

Most of the training, which has been coordinated with property owners where it’s happening, will be out of public view. The training began Sunday, Aug. 19, and continues through Sept. 1. Starting this Sunday, it may become more visible when “helicopters begin supporting the training,” the releases said.

People in St. Paul and Minneapolis might see or hear military transport helicopters — Black Hawks and smaller Hughes 500s — between 7 p.m. and midnight.

Police aren’t releasing exact training times or locations for safety reasons.

Mara H. Gottfried can be reached at 651-228-5262. Follow her at twitter.com/MaraGottfried or twitter.com/ppUsualSuspects.