In what some call an intensifying standoff between police and protesters, a large crowd, some chanting "Hands up, don't shoot," gathered Tuesday where St. Louis police officers shot and killed a knife-wielding man after a reported convenience store robbery.

The shooting happened just a few miles from Ferguson, Missouri where the fatal shooting of an unarmed black teen, Michael Brown, by a white police officer, Darren Wilson, has touched off days of sometimes violent protests. The shooting came after the arrest of 52 people in 24 hours, according to St. Louis County police. Of those arrested, the police said 27 percent were not from Missouri and 93 percent were not from Ferguson.

At least 10 journalists from news outlets including Al Jazeera America, Washington Post and Getty Images have been detained in the last 11 days of protesting.

Attorney General Eric Holder is expected to arrive in Ferguson on Wednesday to address mounting violence between police and protesters.

St. Louis Police Capt. Ed Kuntz said police responded shortly after noon after a report of a robbery at a convenience store. The suspect, a 23-year-old black man, refused police orders to drop the knife, Kuntz said. When the man allegedly raised the weapon and moved toward the officers, both opened fire, killing him, said Kuntz.

Police Chief Sam Dotson said the man was acting erratically and told officers to "shoot me now, kill me now." A man who said he witnessed the shooting, Robert Addison, 36, said the suspect cursed officers as he told them, "You'll have to kill me."

Both officers were placed on administrative duty, pending an investigation, but Kuntz said the shooting appeared to be justified.

About 100 people gathered at the site within an hour of the shooting. Some chanted "Hands up, don't shoot," which has become the mantra of protesters in Ferguson after witnesses described Brown as having his hands in the air when he was shot Aug. 9.

Wilson has been on paid administrative leave since the shooting. The results of an investigation into the shooting could be turned over to a grand jury as early as Wednesday, though it isn't clear whether Wilson will be charged.

Al Jazeera field producer David Douglas reports having seen a number of uniformed St. Louis County police officers patrolling the streets of Ferguson Tuesday without wearing badges. The county police department has not, thus far, returned calls for comment.

Police fired tear gas and stun grenades overnight at protesters as clashes continued in the town still reeling from the shooting. Demonstrations, mostly peaceful but with spasms of violence by smaller groups, have taken place daily since the shooting.

During a press conference held after 3 a.m. local time (4 a.m. Eastern time) Tuesday, Missouri Highway Patrol Capt. Ron Johnson said the evening began with about 200 protesters who were loud but peaceful. After 9:30 p.m., he said a small number of people, whom he described as "criminals," amid the protesters threw bottles and Molotov cocktails.

He said several shots were fired and two guns were confiscated, but he maintained that police did not fire their weapons. He said SWAT vehicles were used to move a gunshot victim from the crowd to safety. The guns and a Molotov cocktail were displayed for the media. Some of the people arrested came from New York and California, Johnson said.

Amid the clashes Monday night, at least two journalists were detained — the latest in a string of media arrests in the last week that have drawn criticism. Online news publication The Intercept released a statement early Tuesday morning saying one of its reporters, Ryan Devereaux, had been handcuffed and placed in a police vehicle. He was subsequently released without charge, along with German journalist Lukas Hermsmeier, who had been similarly detained.

During Monday’s unrest, clouds of tear gas engulfed the streets, and police ordered news media to clear the scene, citing the risk from gunfire that had been reported. National Guard troops could be seen walking on the fringes of the gathering, keeping a distance from protesters.

Al Jazeera and wire services

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