US police kill suspect near Ferguson

St Louis - Police in the US city of St Louis shot dead another suspect on Tuesday, a short distance from a suburb that is the scene of protests over the killing of an unarmed black teenager.

The suspect was a 23-year-old African American man. Sky News reports that the man walked out of a convenience store with two energy drinks in hand, and apparently had not paid for them.

He walked erratically up and down the street, where various business owners proceeded to phone the police when they saw that he had a knife in his hand.

St Louis Police Chief Sam Dotson said in a tweet that officers had responded to a call and found an apparently agitated man, armed with a knife who yelled "kill me now" and approached the patrol.

In a tweet from his own account retweeted by his force, Dotson said: "Officers gave suspect verbal commands. Officers feared for their safety and both officers fired their weapons. Suspect is deceased."

Fox News meanwhile reports that US Attorney General Eric Holder is heading to Ferguson to take the lead in the federal government’s response to the escalating tension.

Holder, who is expected in St Louis on Wednesday, is said to be committing what is being described as an “extraordinary” effort to investigate the case.

President Barack Obama has called for calm on both sides, urging protesters to stay peaceful and police to show restraint.

The world's media descended on the street where the latest police shooting took place, dozens of reporters having been in the nearby St Louis suburb of Ferguson covering the ongoing unrest.

Onlookers gathered at the yellow incident tape sealing off the scene of Tuesday's shooting outside a convenience store in St Louis, some of them chanting the slogan of the protests: "Hands up, don't shoot".

Captain Ed Kuntz told reporters at the scene that an investigation had been launched, but, based on what he had heard, "it seems reasonable to say it was justifiable".

"Whenever there's a police shooting, tensions are always more high," he admitted, while insisting: "Right now we are focused on preserving life and protecting property."

On 9 August, a white officer in Ferguson shot and killed an 18-year-old unarmed black student, triggering more than a week of sometimes violent protests against heavy-handed police tactics.