COUNTY police in riot gear and armoured tanks gave way to state troopers walking side by side with thousands of protesters in the St Louis suburb of Ferguson today.

The dramatic shift came after Missouri governor Jay Nixon assigned policing of the protests to the state highway patrol.

He stripped the St Louis County Police Department of its authority after four nights of clashes with furious crowds protesting against the weekend death of black teenager Michael Brown.

The protests saw four nights of violent policing by officers in full riot gear, who fired tear gas and smoke bombs.

But yesterday’s march was supervised by black highway patrol captain Ron Johnson, who grew up in the community.

“We’re here to serve and protect,” Captain Johnson said. “We’re not here to instil fear.”

The shooting had stoked tensions in Ferguson, where two-thirds of the 21,000 residents are black but all but three police officers are white.

St Louis County Police have previously been accused of racial profiling and racist hiring procedures.

Solidarity vigils have been held in more than 90 cities across the country.

Rallies took place in Detroit, Los Angeles and New York, where people were asked to wear a red ribbon as a mark of solidarity with the the people of Ferguson.

US President Barack Obama said there was “no excuse” for police in Ferguson to use excessive force.

“Now is the time for an open and transparent process to see that justice is done,” he said.