One person was shot and seven people were arrested as fresh violence flared in the riot-hit US town of Ferguson on Sunday, one week after the racially-charged police shooting of an unarmed black teenager.
Police in the strife-torn Missouri community said the shooting victim was in critical condition after being shot by an unidentified attacker.
The incident came as police used smoke bombs and tear gas to disperse around 200 demonstrators who had defied a curfew imposed by Missouri Governor Jay Nixon.
Violence has simmered since the shooting death of Michael Brown on August 9 by a white police officer, which has renewed a national debate about law enforcement and African Americans.
Police in Ferguson also drew criticism for facing down protesters in military-grade armored trucks while brandishing high-powered weapons.
Nixon told CNN on Sunday tensions in Ferguson were likely to remain high, citing the community response as "raw and appropriate." "This is a horrific shooting, we're not to justice yet and there will be moments of energy and angst over the coming days and weeks," he told CNN's "State of the Union".
Nixon had declared a state of emergency and a curfew starting at midnight Saturday (0500 GMT Sunday) until 5:00 am.
Local media reported Sunday the curfew would again be in force for a second night from midnight to 5:00 am (0500 to 1000 GMT Monday).
The latest clashes began when riot police moved to break up a rowdy crowd of protesters who had gathered post-curfew near where Brown was killed.
Missouri Highway Patrol Captain Ron Johnson, the African-American officer Nixon put in charge of restoring peace in Ferguson, said police acted after receiving reports of a shooting and that armed individuals had broken into a restaurant.
"We have a shooting victim in critical condition that may lose her life," said Johnson, speaking to reporters around 3:50 am (0750 GMT).
"We had a subject standing in the middle of the road with a handgun. We had a police car shot at tonight. And, yes, I think that was a proper response tonight, to maintain officer safety and public safety." Seven people were arrested for failing to disperse, he said.
Ready for a fight
Antonio French, an area politician who was with the protesters when police moved in, wrote that some were ready for violence.
"I can tell you firsthand that some of the people that remained tonight were armed. Were ready for a fight. And wanted to injure police," he wrote on Twitter.
He also wrote: "It's important to differentiate the protestors from those violent opportunists that are not thinking about #MikeBrown or justice. #Ferguson." Brown's family has accused authorities of a "devious" attempt to smear their son's character after police named Brown as a suspect in the robbery of a Ferguson convenience store and released a surveillance video of the robbery.
Police said the officer, who did not know of the robbery, stopped the teen merely for walking in the middle of the street.
The video's release sparked widespread criticism, with even governor Nixon saying he was unaware ahead of time and "unhappy" when it came out.
"It appeared to, you know, cast aspersions on a young man that was gunned down in the street," he said on ABC's "This Week," blaming the move for sparking violence Friday night after Thursday's calm.
"It made emotions very raw," he told ABC.
The Justice Department, which is conducting a separate investigation into the shooting, had urged the Ferguson police not to release the video, the New York Times reported, citing a federal law enforcement official.
Attorney General Eric Holder ordered a federal autopsy on Brown's body at the request of his family, the Justice Department said Sunday.
The news was cheered by some civil rights leaders, including NAACP president Cornell Brooks, who called the decision "very encouraging." People "want to know that there are people in the White House who are listening to them, because they don't trust local authorities," he told CBS "Face the Nation."