Image copyright AFP Image caption A 20-year-old man walked into a Walmart store in Springfield, Missouri, carrying a rifle and ammunition

US police have arrested a man who walked into a Walmart store in Missouri armed with a loaded rifle and 100 rounds of ammunition on Thursday.

Although the man, who also wore body armour, did not fire any shots, his actions sparked panic amongst shoppers.

The incident comes less than a week after a mass shooting in an El Paso Walmart in Texas, in which 22 people were killed by a gunman.

The man in Springfield was arrested after walking out of the store.

On Friday, Springfield police named the man as 20-year-old Dmitriy Andreychenko and said he had been arrested for making a first degree "terrorist threat".

"The case is currently under review by the Greene County Prosecutor. Once formal charges are filed by the Greene County Prosecutor's Office more detailed information will be released," police said in a statement.

Image copyright Greene County Police Image caption Dmitriy Andreychenko was arrested for "making a terrorist threat"

Police said Mr Andreychenko was "detained by an armed off-duty fireman until officers arrived on scene" and arrested him.

It was not clear what his motives were.

"His intent obviously was to cause chaos here, and he did that," Lt Mike Lucas of the Springfield police department told the Springfield News-Leader.

The man, who wore a bullet-proof vest and military-style clothes, was filming himself walking through the store and making comments to people while pushing a shopping trolley as shoppers fled around him, Lt Lucas said.

He was also carrying another gun, reports say.

Springfield resident Julie Belew told the News-Leader she saw the man with a rifle walking toward the parking lot as another man, who she believes was the off-duty fireman, had his handgun out.

Ms Belew said someone asked the man "why are you walking around in a tactical jacket carrying a rifle?" but she did not hear his response.

When police arrived, the man told them "he was keeping his phone on for his own safety", Ms Belew said, adding that the young man did not appear surprised or upset.

"He looked like he had accomplished whatever he wanted to accomplish."

She told the newspaper she felt less upset since the man with the handgun was there and the police response was quick.

Media playback is unsupported on your device Media caption Police were filmed responding to the El Paso shootings

On Wednesday, President Donald Trump visited El Paso, where a gunman had opened fire with an assault-style rifle in a crowded Walmart on the city's east side.

Nearby businesses were placed on lockdown and shoppers were evacuated.

In total, 31 people died in the attacks in El Paso and in the Ohio city of Dayton, which took place within hours of each other.