(Adds National Guard sent in, schools closing, police comment)
By Ellen Wulfhorst
FERGUSON, Missouri, Aug 18 (Reuters) - Missouri's governor said on Monday he would send the National Guard into the St. Louis suburb of Ferguson where authorities used tear gas and smoke bombs to disperse a crowd protesting last week's fatal shooting of an unarmed black teen by police.
In an executive order signed after midnight, Governor Jay Nixon said he was dispatching the U.S. state militia to help restore peace after demonstrators threw Molotov cocktails and shot at police as well as a civilian, a description of the protest that differed widely from some eyewitness accounts.
"Tonight, a day of hope, prayers, and peaceful protests was marred by the violent criminal acts of an organized and growing number of individuals, many from outside the community and state, whose actions are putting the residents and businesses of Ferguson at risk," he said in a statement on his website.
At around dusk on Sunday, hundreds of protesters including young children fled to safety after police wearing gas masks and body armor fired canisters of smoke to scatter them hours ahead of a planned midnight curfew in suburban Ferguson, Missouri.
Gunfire was heard by a Reuters reporter and photographer but it was unclear where it was coming from.
A crowd of about 400 appeared to be marching peacefully, and included numerous families with children, when they were subjected to rounds of smoke canisters.
"The smoke bombs were completely unprovoked," said Anthony Ellis, 45. "It (the protest) was led by kids on bikes. Next you know, they're saying, 'Go home, Go home!'"
The Missouri Highway Patrol said "aggressors" were trying to infiltrate a law enforcement command post and that armored vehicles were deployed to ensure public safety.
"We ordered them back. We ordered them back again. After several attempts, we utilized the smoke to disperse these individuals," said Highway Patrol Corporal Justin Wheetley.
He later said that at least one Molotov cocktail had been thrown at police, although some witnesses said those were tear gas canisters being thrown back at police.
"Molotov cocktails were thrown, there were shootings, looting, vandalism, and other acts of violence that clearly appear not to have been spontaneous," State Highway Patrol Captain Ron Johnson told a late night news briefing. "I had no alternative but to elevate the level of our response."
Schools in Ferguson would be closed on Monday, officials said.
The midnight curfew was imposed for the second night in the tense St. Louis suburb hit by racially charged protests, violence and looting since Michael Brown, 18, was shot to death on Aug. 9 by white police officer Darren Wilson.
FEDERAL AUTOPSY, INVESTIGATION
Earlier on Sunday, U.S. Attorney General Eric Holder ordered a federal autopsy of Brown's body, seeking to assure the family and community there will be a thorough investigation.
Police say Brown was asked by Wilson to move off the road and onto a sidewalk and that Brown reached into a patrol car and struggled with Wilson for his service gun and was shot.
A friend of Brown's, Dorian Johnson, 22, and at least one other witness said Wilson reached out through his car window to grab at Brown and the teenager was trying to get away when shot. Brown held up his hands in a sign of surrender but Wilson got out of his patrol car and shot Brown several times, they said.
A preliminary private autopsy, asked for by Brown's family, shows the teenager was shot at least six times, the New York Times reported on Sunday night.
Citing Dr. Michael M. Baden, former chief medical examiner for the City of New York, the newspaper reported that Brown was shot twice in the head, and that the bullets that hit him did not appear to have been fired from very close range because no gunpowder was detected on his body.
That conclusion could change, however, if gunshot residue is found on Brown's clothing, the newspaper said.
Police in Ferguson have come under strong criticism for Brown's death and their handling of the aftermath.
Johnson, the Highway Patrol captain charged with restoring order, told hundreds of people at a local church for a rally on Sunday he was committed to protecting their right to protest.
"I'm sorry," Johnson, who is black, told Brown's family during remarks that prompted repeated standing ovations at the rally. "My heart is heavy."
The mood at the rally was somber as a choir sang gospel music at Greater Grace Church. Rev. Al Sharpton, the civil rights activist, asked participants to join hands and prepare themselves for difficult days ahead.
In St. Louis on Sunday, about 125 people attended a rally in support of officer Wilson, the St. Louis Metropolitan Police Department said. Protesters held signs that read, "We love and support you Darren" and "Support our police. Pray for peace."
Police also used smoke canisters and tear gas on Saturday to disperse protesters who refused to leave the area when the midnight-to-5 a.m. curfew began. Seven protesters were arrested after failing to disperse.
Nixon, a Democrat, criticized Ferguson police for releasing a video on Friday purporting to show Brown taking part in a convenience store robbery shortly before the shooting. Police have said the officer who shot Brown had no idea he was a robbery suspect.
As disturbances continued in Missouri, 500 people protested outside police headquarters in Los Angeles on Sunday over the shooting death of an unarmed black man in California a week ago.
That rally was peaceful, with many holding up signs reading, "Hands up, don't shoot," in reference to witness reports that Brown had his hands up when he was shot in Ferguson. (Additional reporting by Lucia Mutikani and Julia Edwards in Washington, Victoria Cavaliere in Seattle and Dana Feldman in Los Angeles; Writing by Colleen Jenkins and Sharon Bernstein; Editing by Mark Heinrich)