Four law enforcement officers have been fatally shot and four others were wounded while serving a warrant in Charlotte, North Carolina, officials say.
At least one suspected attacker was found dead in the front yard of a barricaded home after a standoff that lasted three hours, police said.
Authorities said two armed suspects were involved.
It is one of the deadliest assaults on US law enforcement in decades.
The officers were part of a US Marshals Service-led task force who were attempting to serve a warrant on Monday against a felon wanted for illegally possessing a firearm when gunfire erupted on the suburban street.
The officers returned fire at an assailant in the front yard, then more shots were fired at them from inside the home, Charlotte-Mecklenburg Police Chief Johnny Jennings told a news conference. A high-powered rifle was found inside the property, he added.
“Today we lost some heroes who were out simply trying to keep our community safe,” the police chief told reporters.
He said it was the worst attack on police officers he could recall in his 30 years on the force.
Shots were still ringing out more than two hours after the attack began in a residential area in the east of the city, according to witnesses.
The assault ended when police stormed the home on Galway Drive in the Shannon Park neighbourhood, using armoured vehicles to smash their way in, destroying windows and doorways.
Two other people – a woman and a 17-year-old boy – who were inside the home with a suspect were being questioned, said police. It is believed at least one of them shot at officers.
The US Marshals Service confirmed in a statement that one of its officers had been killed in the raid.
North Carolina Governor Roy Cooper said two of the officers killed were members of the state’s Department of Adult Corrections.
“Our hearts are with the families and co-workers of officers in today’s brutal attack,” he posted on X, formerly Twitter.
Also killed was Charlotte-Mecklenburg Police Department Officer Joshua Eyer, who had served on the force for six years, police said.
“We are forever indebted to Officer Eyer for his bravery and ultimate sacrifice,” a police statement said.
Chief Jennings said on Monday afternoon: “A lot of the questions that need to be answered, we don’t even know what those questions are now.
“We have to get a full understanding of why this occurred and also uphold the integrity of the investigation.”
Several nearby schools were placed on lockdown during the siege.
Residents were asked to shelter in place and nearby streets – including Interstate 77 – were closed to facilitate ambulance rescues.
Witness Tyler Wilson told CBS News he was working at home when he heard police shout for the suspect to come out of the house.
“After that, it was just chaos,” he said. “There was shots ringing left and right.
“We had Swat, and US Marshals set up snipers in our bedrooms. There was an officer [that] got dragged by his arms through our house.”
“It’s been pretty crazy,” he continued. “It was about 30 minutes where it was a straight shootout.”
Charlotte Mayor Vi Lyles said she spoke to President Joe Biden, who passed his condolences to the community.
The mayor said in a statement that she was “deeply saddened” by the shooting.
