POLICE charged crowds of protesters and arrested 47 people in the early hours today in the St Louis suburb of Ferguson.

Protesters were fewer than during the previous nights of demonstrations since 18 year-old Michael Brown was shot dead 11 days ago.

But Captain Ron Johnson of the Missouri Highway Police claimed bottles of water and urine had been thrown at police, prompting officers to intervene. 

“As of 1am we have 47 arrests,” he told reporters, adding that three guns had been taken from demonstrators.

Captain Johnson said there had been no shots fired during the evening and tear gas had not been used by police.

Police restraint in the use of tear gas had led to a calmer atmosphere but tensions rose as news of yet another police shooting spread through the crowd of several hundred protesters.

Police shot dead a knife-wielding 23-year-old African-American male in St Louis following reports of a robbery on Tuesday evening.

According to police the suspect ignored orders to drop the knife and continued to approach the officers, coming “within three to four feet” before officers opened fire, said St Louis Police Chief Sam Dotson.

The man was heard shouting “kill me now” as he moved towards police.

Meanwhile, US Attorney General Eric Holder arrived in Missouri following his promise of a thorough investigation into Mr Brown’s shooting.

And a grand jury started hearing witnesses to the killing, amid calls for police officer Darren Wilson to be put on trial for murder.