A man carrying a “tactical rifle” and clad in body armor sparked chaos when he walked into a Missouri Walmart on Thursday, police said — less than a week after a gunman stormed a Walmart in El Paso, Texas.

The man, who is in his 20s, sent terrified shoppers running from the Springfield store when he showed up around 4 p.m.

He was detained by an armed off-duty firefighter and later placed under arrest, according to police.

No shots were fired and no injuries were reported, Springfield police said in a statement.

Investigators were working to determine the man’s motive, and the investigation was ongoing, cops added.

The incident came less than a week after racist gunman Patrick Crusius allegedly killed 22 people at an El Paso, Texas, Walmart on Saturday. He posted an anti-Hispanic screed online minutes before the slaughter.

Gun-related incidents have surged at Walmarts nationwide, with four others reported since Saturday’s shooting.