“His intent obviously was to cause chaos here, and he did that," police said.

Greene County Sheriff's Office Dmitriy Andreychenko

A man clad in body armor and carrying "tactical weapons" was arrested Thursday after sparking mass panic at a Walmart in Missouri — less than a week after 22 people were killed in a shooting at an El Paso Walmart. Dmitriy Andreychenko, 20, was carrying guns loaded with more than 100 rounds of ammunition, KY3 reported. He grabbed a shopping cart upon entering the store and started recording himself on a cellphone while walking the aisles.

Though shots were not fired, chaos ensued, and terrified shoppers reportedly ran out of the Walmart after the store manager pulled a fire alarm to warn them. An off-duty firefighter detained Andreychenko at gunpoint outside the store, and police then took him into custody, authorities said. "This was a reckless act designed to scare people, disrupt our business and it put our associates and customers at risk," a spokesperson for Walmart said in a statement, adding that the suspect is no longer welcome in stores. "We are working with the authorities however we can and we appreciate their quick response that prevented this situation from escalating further," the retailer said.

nbcnews.com Dmitriy Andreychenko being arrested outside the Walmart.

Andreychenko was charged Friday with making a terrorist threat in the second degree, a felony, the Greene County Prosecuting Attorney's Office said.

Open carry of firearms is legal in Missouri, "unless the firearm is intentionally displayed in an angry or threatening manner," according to state law. "Missouri protects the right of people to open carry a firearm, but that right does not allow an individual to act in a reckless and criminal manner endangering other citizens," Greene County Prosecuting Attorney Dan Patterson said in a statement. If convicted, Andreychenko faces up to 4 years in state prison and a fine of up to $10,000. Lt. Mike Lucas told reporters at the scene Thursday that Andreychenko's "intent obviously was to cause chaos here, and he did that." "His intent was not to cause peace or comfort to anyone that was in the business here — in fact, he's lucky he's alive still, to be honest," Lucas said. A woman at the scene, Julie Belew, told the Springfield News-Leader she was in her car outside the store when she saw the man's arrest.

"He did not seem surprised. He did not seem angry. He looked like he had accomplished whatever he wanted to accomplish," Belew said. Police declined to confirm details of the incident to BuzzFeed News, saying it was "too early in the investigation to determine a motive." According to a probable cause statement filed in court Friday, Andreychenko told police he was recording himself in case somebody tried to stop him and tell him to leave. "I wanted to know if that Walmart honored the 2nd Amendment," Andreychenko said, according to the documents. He told police he had intended to buy grocery bags and didn't think people would react the way that they did. "This is Missouri, I understand if we were somewhere else like New York or California, people would freak out," he said. Andreychenko is vehemently pro-gun, according to his social media pages.

Widely circulated screenshots of a Facebook post reportedly made by Andreychenko railed against Walmart for raising the age limit for buying a gun from 18 to 21 in February. BuzzFeed News was not able to independently verify the post was written by the suspect, as his Facebook page was made private by Friday.