#BlackLivesMatter marches on despite attack against US police

Thousands of protesters continued to march on US streets on Friday to protest the killing of an African-American by police officers, despite an attack that saw a gunman kill five officers. 

Demonstrators marched and held candlelight vigils across major cities as President Barack Obama interrupted a foreign trip, travelling to Dallas where scenes of horror emerged this week.

Vast crowds marched in Houston, New Orleans, Detroit, Baltimore, and San Francisco with several solidarity marches held in cities across the world including London.

Atlanta witnessed the biggest turnout where protesters blocked a major road.

Protests erupted when a video emerged showing police officers killing an unarmed African-American - the 609th since January this year, according to statistics from Cop Crisis.   

Chaos swept over largely peaceful protests against the killing of Alton Sterling when a black army veteran shot dead five officers as thousands demonstrated in Dallas, urging calls to mend troubled race relations in the United States.

Protests erupted when a video emerged showing police officers killing an unarmed African-American - the 609th since January this year

Police allege they retrieved bomb-making materials and a weapons cache at the home of 25-year-old Micah Johnson, a Dallas area resident who gunned down the officers before being killed by a robot controlled by the force.

Seven other officers and two civilians were wounded on during the rallies on Thursday.

Police described Johnson  as a "loner" with no prior criminal record and was a US Army reservist for six years during which he served in Afghanistan.

Leaders of the Black Lives Matter protest movement condemned the Dallas violence, but vowed to go ahead with planned weekend marches.