This weekend should see even more mayhem as 6,000 are expected to attend “weekend of resistance” events in and around Ferguson.

(Reuters) – Police clashed with protesters in St. Louis on Thursday for a second night after an officer killed a black teenager, ahead of a weekend of planned rallies in the area over the August killing of unarmed black teenager Michael Brown.

Throughout the night, as many as 400 demonstrators spread out across several city blocks in south St. Louis, angrily shouting and chanting at rows of police officers, many of whom were clad in riot gear.

Dozens of protesters had met earlier at the site in the Shaw neighborhood where 18-year-old Vonderrit Myers Jr. was shot dead on Wednesday by an off-duty white officer working for a private security firm in what police described as a firefight.

But demonstrations grew increasingly chaotic. At one point early on Friday morning, a line of police pushed toward a group of several dozen protesters who jeered and cursed at them, pepper-spraying those who refused to disperse.

St. Louis Police Chief Sam Dotson told local television station Fox 2 that at one point during the tense protest, someone behind the massive crowd threw a knife that struck an officer’s body vest at the shoulder.

He added that a police car and several businesses and residences had been damaged and that U.S. flags were burned. Two people had been arrested by midnight local time, Dotson said, during which one officer suffered minor injuries.

With a not-so-veiled threat of violence this weekend from the protest organizers:

“We never advocate violence … But I do know that people were angry last night and they will be out this weekend,” said Tory Russell, a leader of Hands Up United. “I don’t know what they are going to do.”