Authorities said two St. Louis city police officers shot and killed a black man who came within several feet of them brandishing a knife on Tuesday in a confrontation a few miles from the turbulent suburb of Ferguson.

A 23-year-old man brandishing a knife was shot and killed by a St. Louis police officer Tuesday afternoon, according to the St. Louis police department

The suspect was acting erratically and refused to put down the weapon, according to authorities. Police Chief Sam Dotson said via Twitter that an officer gave verbal commands, and both officers "feared for their safety" before firing their weapons.

At a news conference, Dotson said the suspect held a knife overhead in "a threatening manner" as he approached at least two officers.

It was not clear how many shots were fired, and Dotson did not disclose the race of the man who was shot or of the officers. Both officers opened fire, and no one else was injured, Dotson said.

The incident unfolded in the shadow of Ferguson, where police and civilians have clashed since Aug. 9, when a white police officer shot and killed Michael Brown, an unarmed young black man who witnesses have said had his hands up when he was gunned down.

As Dotson spoke, shouts could be heard off-camera, and reporters repeatedly asked the chief if he feared similar unrest in St. Louis. City Alderman Antonio French, who has been heavily involved in the protests in Ferguson, said on Twitter that a crowd was already forming at the scene of Tuesday's shooting.

At one point Dotson was asked if he thought Missouri Gov. Jay Nixon should consider deploying the National Guard in the city.

“I think this is an incident that happened in the city of St. Louis," Dotson said.

At least one witness to the incident told police that the suspect may have been intentionally trying to provoke the police into shooting him. Dotson said the man was acting erratically before the shooting occurred.

"Shoot me, kill me now," the man said, according to Dotson.

Both officers have been placed on administrative leave and Dotson said he would try to make information available as quickly as possible. Based on the preliminary facts, though, Dotson seemed to suggest the officer's actions were justified.

“If a person is charging you with a knife and they’re within three or four feet, that’s a lethal range for a knife," he said.

The man's identity was not released, but Dotson described him as a 23-year-old male.

An investigation is ongoing.