Officers arrested at least nine people and deployed tear gas amid protests in St. Louis over the death of a black 18-year-old who was fatally shot by police after he pointed a gun at them, the city's police chief said.

Chief Sam Dotson said at a press conference late Wednesday night that a group of protesters who had blocked an intersection threw glass bottles and bricks at officers and refused orders to clear the roadway. Inert gas was used and when that didn't have any effect on the crowd, police turned to tear gas to clear the intersection, Dotson said. Those arrested face charges of impeding the flow of traffic and resisting arrest, he said.

The demonstration was one of several Wednesday after the killing of 18-year-old Mansur Ball-Bey of St. Louis. It comes with tensions already high in the area after violence erupted during several events marking the anniversary of the death of Michael Brown, the 18-year-old fatally shot last year by a police officer in nearby Ferguson.

Two police officers serving a search warrant Wednesday afternoon at a home in a crime-troubled section of the city's north side encountered two suspects, one of which was Ball-Bey, the chief said. The suspects were fleeing the home as Ball-Bey, who was black, turned and pointed a handgun at the officers, who shot him, Dotson said. He died at the scene.

Both officers, who are white, were unharmed, according to a police report.

Police are searching for the second suspect, who they said is believed to be in his mid- to late teens.

Dotson said four guns, including the handgun wielded by the dead suspect, and crack cocaine were recovered at or near the home, which last year yielded illegal guns during a police search.

A man and woman who were also inside the home were arrested, Dotson said.

Roughly 150 people gathered Wednesday afternoon near the scene of the shooting, questioning the use of deadly force. Some chanted "Black Lives Matter," a mantra used after Brown's death.

As police removed their yellow tape that cordoned off the scene, dozens of people converged on the home's front yard, many chanting insults and gesturing obscenely at officers. Several onlookers surrounded individual officers, yelling at them.

"Another youth down by the hands of police," Dex Dockett, 42, who lives nearby, told a reporter. "What could have been done different to de-escalate rather than escalate? They (police) come in with an us-against-them mentality. You've got to have the right kind of cops to engage in these types of neighborhoods."

Another neighborhood resident, Fred Price, said he was skeptical about Dotson's account that the suspect pointed a gun at officers before being mortally wounded.

"They provoked the situation," Price, 33, said. "Situations like this make us want to keep the police out of the neighborhood. They're shooting first, then asking questions."

In addition to the nine arrests at the Wednesday night demonstration, officers responded to reports of burglaries in the area and the fire department was called after a car was set ablaze, according to Dotson.

He blamed the crimes on people seeking "notoriety" in a neighborhood "plagued by violence."

The area is near where a 93-year-old veteran who was part of the famed Tuskegee Airmen — the U.S. military's first black aviators — was the victim of crimes twice within a few minutes Sunday, being robbed and then having his car stolen. The veteran was unhurt, and his car was found Tuesday blocks from where it was taken.

Protests have become a familiar scene across the St. Louis region since Brown, who was black and unarmed, was fatally shot by Ferguson officer Darren Wilson on Aug. 9, 2014. A St. Louis County grand jury and the U.S. Justice Department declined to charge Wilson, who resigned in November.

Some of those who protested Ball-Bey's killing had already spent the morning in downtown St. Louis, marching to mark the anniversary of the fatal police shooting of Kajieme Powell. He was fatally shot by two St. Louis officers after police said he approached them with a knife. Circuit Attorney Jennifer Joyce is still reviewing the case to determine whether lethal force was justified.

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Associated Press reporter Jim Suhr contributed to this report.