Three people were killed Wednesday evening in a shooting inside a Walmart supermarket in Thornton, a Denver suburb in the U.S. state of Colorado, according to local media reports.
Police were called to the Thornton Walmart store around 6:00 p.m. (2400 GMT), according to KMGH TV. The store was evacuated after police arrived at the scene.
Thornton Police Department initially announced around 6:30 p.m. (0030 GMT, Thursday) that "multiple parties" were down in the shooting.
An hour later, they tweeted "at this time this is not an active shooter" and confirmed two adult men were dead and another women was injured in the fatal incident.
In a video clip posted online, an employee of the Walmart told local TV that he heard probably five or six shots at least.
"Everyone got down, everyone started screaming, it was crazy!" he said.
Denver 7 news channel cited a Homeland Security official as saying that it is yet to know any terrorism links at this time.
So far, there is no suspect in custody, the official said.
The shooting incident triggered a new wave of advocate for gun control on social media.
A user named NyxSea tweeted "this is how mass shootings have become normal in the US. When I read that there was 1 death #ThorntonWalmartShooting I said thank God."
"Thanks to @NRA lobbyists and lawmakers beholden to them, THIS is what America looks like. THIS is every city, every day," tweeted Shanon Watts, founder of Moms Demand Action for Gun Sense in America, a grassroots organization working to end gun violence.
The state of Colorado witnessed a mass shooting in July 2012. Twelve people were killed and 59 others injured in Aurora, a suburb 10 miles (16 km) east of Denver, where a heavily armed gunman burst into a packed theater and sprayed the audience with bullets.
According to the non-profit organization Gun Violence Archive, there have been 299 mass shooting incidents so far this year in the United States. Also on Wednesday, two people were shot dead near a college in the Manhattan borough of New York City.
The country now is split on whether to have controls on guns or follow the 1789 Second Amendment of the U.S. Constitution which protects the right of the people to keep and bear arms.