(Adds details from demonstration, comments by police captain)
By Nick Carey
FERGUSON, Mo., Aug 14 (Reuters) - Missouri's governor moved to ease tensions on Thursday after days of racially charged protests over the police shooting of an unarmed black teenager, putting the African-American captain of the Highway Patrol in charge of security in the St. Louis suburb of Ferguson.
Captain Ron Johnson, who grew up in Ferguson, told reporters he would take a "different approach" to policing after complaints that officers used heavy-handed tactics, arresting dozens of protesters and using teargas and pepper pellets to break up crowds.
Protesters filled the streets for a fifth night on Thursday in the mostly black suburb of Ferguson and also assembled in other U.S. cities following the death of 18-year-old Michael Brown last weekend.
The mood was boisterous but peaceful, even festive at times, in sharp contrast to tense nightly standoffs between heavily armed riot police flanked by armored cars and angry protesters, as well as episodes of looting, vandalism and violence.
Thousands of demonstrators, including more white protesters than on previous evenings, gathered late into the night near the site of Saturday's shooting.
In sharp contrast to Wednesday night's heavy deployment by riot police, Captain Johnson and a handful of African-American officers without body armor walked among the crowd.
"We just want to be able to come and demonstrate together without the fear of being shot. It's that simple," said 53-year-old protester Cat Daniels, an Iraq veteran. "What you see tonight is people coming together. When that kid was killed the hurt and the pain was real."
In the forecourt of a gas station burned out during rioting earlier this week, a cowboy rode a horse and a group of children danced on pavement covered in chalk drawings with the words: "Now the world knows your name, RIP Mike."
Elsewhere drivers honked horns and waved signs in solidarity and one group of demonstrators even took to the streets on a car-sized replica of the fictional steam locomotive Thomas The Tank Engine.
"It's because of this young man right here," Captain Johnson told a CNN reporter, holding up a picture of Brown to shouts of approval from protesters around him. "It's about the justice for everyone."
The protests have cast a spotlight on racial tensions in greater St. Louis, where civil rights groups have complained in the past that police racially profiled blacks, arrested a disproportionate number of blacks and had racist hiring practices.
Brown's shooting galvanized a national moment of silence and rallies in other U.S. cities.
In New York, a large crowd briefly overwhelmed a small police presence in Union Square park, forcing officers to scramble to close one of Manhattan's major thoroughfares. Local media showed a handful of protesters being arrested.
In St. Louis, CNN footage showed hundreds of people peacefully assembled in the shadow of the iconic Gateway Arch, Brown's mother and other family members among them.
Seeking to defuse the situation earlier on Thursday, U.S. President Barack Obama had called on police to respect peaceful demonstrations.
Missouri Governor Jay Nixon said Ferguson lately "has looked a little bit more like a war zone, and that is unacceptable."
Police have pledged to do better but have also justified the tough tactics, saying they have responded to the threat of violence during protests.
"WHAT'S HIS NAME?"
Protesters have decried what they say is a lack of transparency by police investigating Saturday's shooting, including the refusal to release the officer's name.
On Thursday night in Ferguson, around 200 demonstrators chanted, "what's his name? what's his name?'" at Johnson and the St. Louis County police chief, Jon Belmar.
Police said they plan to release on Friday the name of the officer who shot Brown, according to CNN and Los Angeles Times reports.
Some critics have also called for St. Louis County Prosecuting Attorney Bob McCullough to be removed from the case.
U.S. Attorney General Eric Holder said in a statement that police had accepted an offer of technical assistance from the Justice Department "to help conduct crowd control and maintain public safety without relying on unnecessarily extreme displays of force."
The Justice Department, the FBI and the St. Louis County prosecutor's office are all investigating Brown's death.
A law enforcement official told Reuters that Holder spoke with Michael Brown's parent's by phone as they and their lawyers visited the U.S. attorney's office in Missouri.
Holder expressed his personal condolences for their son's death and promised the department would conduct a full, independent civil rights investigation, the official said.
Early on Thursday, a member of the Anonymous hacker activist collective tweeted the name of a person alleged to be the police officer who shot Brown. But police and other Anonymous tweeters said the activist had named the wrong person.
There is little clarity on what occurred during Saturday's incident. Police have said that Brown struggled with the officer who shot and killed him. The officer involved in the shooting was injured during the incident and was treated in a hospital for swelling on the side of his face, they said.
But some witnesses have said that Brown held up his hands and was surrendering when he was shot multiple times in the head and chest. (Reporting by Nick Carey; Additional reporting by Brendan O'Brien in Milwaukee, David Bailey in Minneapolis, Carey Gillam in Kansas City, Jeff Mason in Edgartown, Mass., Curtis Skinner and Brendan McDermid in New York; Writing by Fiona Ortiz and Eric M. Johnson; Editing by Eric Beech, Ken Wills and Matthew Driskill)