Media playback is unsupported on your device Media caption St Louis County prosecutor Robert McCulloch says they have charged the man responsible for firing the shots.

A man has been arrested in connection with the shooting of two policemen in the troubled city of Ferguson.

Jeffrey Williams, 20, has been charged with two counts of assault and gun violations.

The police officers were wounded when shots were fired at them during a protest on Thursday night.

Ferguson has been a flashpoint for race relations following the shooting of black teenager Michael Brown by a white police officer in August 2014.

Giving details of the arrest, County Prosecutor Robert McCulloh said Mr Williams had admitted to his "participation in firing the shots", but added, "it was not certain if he had been targeting police."

The prosecutor said that Mr Williams claimed he fired the shots from a car in a dispute with other unidentified individuals.

Mr McCulloh added that a weapon had been recovered and that Mr Williams is believed to have been the only shooter.

Mr Williams, an African-American, had taken part in the peaceful demonstration earlier in the evening outside police headquarters.

The protest followed the resignation of Ferguson's police chief after a damning US Department of Justice report found racial bias in his department.

Media playback is unsupported on your device Media caption Eyewitness at the police shooting, Keith Rose: "I saw one officer covered in blood - I saw officers running to the aid of that officer"

The policemen were wounded in the cheek and shoulder, and have since been released from hospital.

President Barack Obama and Attorney General Eric Holder condemned the attack.

Extremely critical report

Police chief Thomas Jackson was the sixth Ferguson official to be fired or step down. He had initially resisted calls from protesters and some state leaders to resign.

Mr Jackson was widely criticised after the shooting of 18-year-old Michael Brown in August and the weeks of demonstrations that followed.

The Justice Department report found substantial evidence of intentional discrimination in the police and justice system.

The report contended that African-Americans were at the receiving end of 90% of officers' use of force.

In November, a St Louis County grand jury found that white police officer Darren Wilson did not break any laws when he shot Brown.

Police across the country have faced criticism following the deaths of a series of black men in contentious circumstances.

Ferguson - key moments

9 August , 2014: White police officer Darren Wilson shoots dead unarmed black teenager Michael Brown

, 2014: White police officer Darren Wilson shoots dead unarmed black teenager Michael Brown 15 August : Authorities identify Mr Wilson, following days of protests and clashes with police

: Authorities identify Mr Wilson, following days of protests and clashes with police 10-13 October : Activists from across US hold four days of rallies and vigils in Ferguson

: Activists from across US hold four days of rallies and vigils in Ferguson 24 November : Grand jury decides not to charge Mr Wilson, triggering further demonstrations

: Grand jury decides not to charge Mr Wilson, triggering further demonstrations 4 March : Department of Justice issues report alleging widespread racial bias in Ferguson police department

: Department of Justice issues report alleging widespread racial bias in Ferguson police department 11 March : Police chief Thomas Jackson announces his resignation

: Police chief Thomas Jackson announces his resignation 12 March: Two police officers are wounded after being at a demonstration

How Ferguson unrest spread

Report on Ferguson police report - key findings