Jon Belmar

Authorities declared a state of emergency in Ferguson, Missouri, after gunfire erupted on the anniversary of a high-profile police shooting and prosecutors on Monday charged an 18-year-old man with assault on officers.

Officials scrambled to head off renewed anger on Wednesday after an armed black teenager was shot dead by a white officer in a St Louis suburb, insisting the use of force was justified.

St. Louis County Police Chief Jon Belmar says at least a dozen businesses are burning after protests in Ferguson turned violent.

The shooting of the black teenager sent hundreds of angry residents out of their apartments in a predominantly black Missouri city in a confrontation with police that lasted several hours. They shouted obscenities and some threats, such as "kill the police," but there were no reports of additional injuries.

Authorities declared a state of emergency in Ferguson, Missouri, after gunfire erupted on the anniversary of a high-profile police shooting and prosecutors on Monday charged an 18-year-old man with assault on officers.

Officials scrambled to head off renewed anger on Wednesday after an armed black teenager was shot dead by a white officer in a St Louis suburb, insisting the use of force was justified.

St. Louis County Police Chief Jon Belmar says at least a dozen businesses are burning after protests in Ferguson turned violent.

The shooting of the black teenager sent hundreds of angry residents out of their apartments in a predominantly black Missouri city in a confrontation with police that lasted several hours. They shouted obscenities and some threats, such as "kill the police," but there were no reports of additional injuries.