The U.S. Department of Justice will lead the investigation into the death of a black man shot multiple times by police during a confrontation at a Louisiana convenience store, the state's governor said.

The family of a black man shot multiple times by police during a fatal confrontation at a Louisiana convenience store called for an independent investigation and officials to resign in the wake of video showing the chilling incident.

Graphic footage circulating online filmed by a witness early Tuesday appears to show Alton Sterling, 37, being shot as two cops pin him to the ground before he is killed.

His death has sparked protests against police brutality in Baton Rouge, and family members and the local NAACP branch called for Louisiana State Police to take over the review from the Baton Rouge Police Department.

"I'm calling on anybody in this city with a backbone to go arrest those two officers," Mike McClanahan, of the local NAACP, said at a news conference Wednesday.

"This is a new day," he added. "We will not have anybody who allows this type of action to take place."

Baton Rouge officials did not immediately respond to the criticism, but a news conference was planned for Wednesday afternoon.

Baton Rouge police said uniformed officers responded to a call after midnight Tuesday about a black male in a red shirt who was selling CDs and had reportedly threatened the caller with a gun.

Officers "made contact" with the 5-foot-11 Sterling in the parking lot of the Triple S Food Mart, and an altercation ensued, police said in a statement.

"Sterling was shot during the altercation and died at the scene," the statement said.

Two officers have been placed on administration leave "per standard procedure," it added, saying the investigation was ongoing.

Sterling died from multiple gunshot wounds to the chest and back, according to East Baton Rouge Coroner Dr. William Clark. He would not immediately confirm reports that Sterling was shot seven times.

The president of the NAACP, Cornell Brooks, called video of the incident hard to watch — but "far harder" to ignore.

"Get on the ground, get on the ground" is heard before two officers confront a man in a red T-shirt. One officer tackles the man, throwing him on the hood of the car and onto the ground. The second officer climbs on and helps hold him down.

One officer appears to shout a warning: "He's got a gun! Gun!"

While the man is on the ground, one officer pulls out his gun. He holds it the back of the man's head or neck, shouting is heard, and then two pops — as the camera quickly cuts away. At least two more pops are heard.

Background voices are heard saying "oh my God" and "They shot him?" and "They killed this boy."

"Oh my God," a woman's voice shrieks.

Sterling is a convicted felon, and wouldn't be permitted to have a gun. Those who knew him said he kept one to protect himself from robbers.

Edmond Jordan, a Louisiana state representative and Sterling family attorney, said whether or not Sterling had a gun is irrelevant at the moment he was pinned because the video doesn't appear to show him wielding a weapon or pulling one out against the officers.

Sterling's sister, Mignon Chambers, said something "needs to be done" in wake of the shooting.

"There's no reason for you to handle him the way that you did," she said. "It wasn't right."

uinyetta Mcmillon, the mother of Sterling's 15-year-old son, said officers handled the incident "unjustly," and told reporters Wednesday that they killed a man who was "simply trying to earn a living and take care of his children."

"I, for one, will not rest or not allow him to be swept in the dirt," Mcmillon said as Sterling's son sobbed behind her.

Sterling had recently been residing in a transitional living center, according to The Advocate newspaper.

Mufleh Alatiyat, an employee of Triple S Food Mart called Sterling generous and said he often gave away CDs or bought food or drinks for other customers, he told The Associated Press.

Some lawmakers said Sterling's family deserves answers for what happened.

State Rep. Ted James called the shooting a "murder," saying in a statement it "has made me question what it really means to be land of the free and home of the brave."

James also demanded an independent investigation and scrutiny of the police department's body-camera policy. Local media reported that the officers' body cameras had fallen off.

State Rep. C. Denise Marcelle, who sponsored the bill to equip Baton Rouge officers with body cameras, said at Wednesday's news conference that she wants police to stop using those body cameras in favor of ones that don't seem to fall off so easily.

Congressman Cedric Richmond cited "a number of unanswered questions" around the "tragedy" — including the level of force and response of officers after.

"The video footage released today of the shooting of Alton Sterling ... was deeply troubling and has understandably evoked strong emotion and anger in our community," Richmond said in a statement. "I share in this anger and join the community in the pursuit of justice.

He called on the U.S. Department of Justice to conduct an investigation — and for protests to be conducted "with dignity."

Protesters gathered outside the convenience store overnight Tuesday, chanting "black lives matter" and holding signs saying "Honk for justice" as car horns blared.

#AltonSterling was trending on Twitter amid the mounting outrage.

Martin Luther King's youngest daughter, Bernie King, was among those adding her voice.

"May his name and his brutal last breath shake up and transform systems," she wrote on Twitter.