The sight of heavily armed officers and troops called in to contain protests, which erupted more than a week after the fatal police shooting of an unarmed black teenager, have been criticised by civil-rights organisations.
Michael Brown was shot in the Missouri suburb of Ferguson earlier this month.
Activists say police forces in the US are over-militarised and are violating the basic right of being able to protest peacefully.
Al Jazeera's Rachel Levin reports from Ferguson.
Source: Al Jazeera