Overnight curfew resumes in tense St Louis suburb

Police have fired tear gas and issued warnings for crowds to disperse as a curfew starts for a second night in Ferguson in the US state of Missouri, the BBC reported.

It is in force from midnight (05:00 GMT) to 05:00 (10:00 GMT).

Police wearing body armour and gas masks said "aggressors" in a crowd of several hundred protesters were advancing on a police command post.

The suburb of St Louis has been tense for more than week, since police shot dead a black teenager, Michael Brown.

US Attorney General Eric Holder has ordered a federal post-mortem on the body of Michael Brown, 18, to take place "as soon as possible."

A preliminary private autopsy report found that Mr Brown was shot at least six times, including twice in the head, the New York Times reports.

Aleem Maqbool reports: ''We've heard the sounds of two loud explosions. It is very chaotic.''

The bullets did not appear to have been shot from very close range due to the lack of gunpowder on the victim's body, forensic pathologist Michael Baden was quoted by the paper as saying.

He flew to Missouri on Sunday to conduct a separate autopsy at the request of the family.