GREENE COUNTY, Mo. — Law enforcement authorities are investigating a suspect identifies as 20-year-old Dmitriy Andreychenko who was armed and wearing body armor and military-style clothing outside a Walmart in Springfield, Mo.

Just after 4 p.m. Thursday, Springfield police officers were dispatched to 3150 W. Republic Road, a Walmart Neighborhood Market, according to a media release.

An armed white male in his 20s was detained by an armed off-duty fireman until officers arrived on scene and took the suspect into custody.

No injuries were reported, and no shots were fired.

Lt. Mike Lucas said that the man walked inside the Walmart carrying a “tactical rifle” and another gun. Lucas said the man had more than 100 rounds of ammunition.

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

Andreychenko is being held on requested charges of first-degree terrorist threat, according to online jail records.

— The AP contributed to this report.