"Given these deliberate, coordinated and intensifying violent attacks on lives and property in Ferguson, I am directing the highly capable men and women of the Missouri National Guard ... in restoring peace and order to this community," he said in a statement.
Gunfire, tear gas and Molotov cocktails Sunday night marked some of the fiercest clashes yet between police and protesters furious about the death of an unarmed teenager.
And the tensions continued escalating after autopsy results revealed that 18-year-old Michael Brown was shot six times.
What began as peaceful protests spiraled into disarray after two civilians were shot and injured, Missouri State Highway Patrol Capt. Ron Johnson said. He said those civilians were not shot by police.
"Tonight, a Sunday that started with prayers and messages of unity, peace and justice took a very different turn after dark," Johnson said early Monday morning.
Some protesters hurled Molotov cocktails at police, and several businesses were vandalized or looted, despite the Brown family's call for calm.
"Based on these conditions, I had no alternative but to elevate the level of our response," Johnson said.
Officers fired tear gas into a crowd of hundreds of protesters, including children, who were marching toward a police command post despite an impending midnight curfew.
But protester Lisha Williams challenged the notion that protesters provoked officers.
"That is a lie. It was no fight, it was no shots fired," she told CNN late Sunday night. "All we did was march to the command center to fall to our knees and say, 'Don't shoot.' And they started shooting."
The clashes kept escalating, with St. Charles County sheriff's officials saying shots were fired in their direction.
At one point, employees at a McDonald's restaurant locked themselves in a storage room after the store was overrun, Johnson said.
Video from CNN affiliate KSDK showed children among the protesters chanting, "Hands up, don't shoot."
St. Louis County police said most of the crowds had dispersed after the curfew went into effect at midnight. The curfew was scheduled to end at 5 a.m. (6 a.m. ET).
But the anxiety remains. Children can't even go to school Monday.
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"Information we received from officials on the scene late Sunday evening has contributed to concerns we have about children walking to school or waiting for buses on streets impacted by this activity," the Ferguson-Florissant School District said on its Facebook page.
Brown, an unarmed black teenager, was shot dead by a white police officer on August 9. He was shot at least six times, including twice in the head, according to the preliminary results of an autopsy that his family requested.
Family attorney Anthony Gray said the independent autopsy conducted Sunday found that Brown was shot twice in the head and four times in the right arm -- all to the front of his body.
Last week, the St. Louis County Police Department said an original autopsy found that the teen died of gunshot wounds. But the department wouldn't say how many times he was shot or give any other details.
According to the preliminary results of the family autopsy, the bullets that struck Brown were not fired from close range, as indicated by the absence of gunpowder residue on his body.
One of the bullets shattered his right eye, traveled through his face, exited his jaw and re-entered his collarbone, according to the autopsy.
The last two shots were probably the ones to his head, attorney Gray said. One entered the top of his Brown's skull, suggesting his head was bent forward when he was struck.
The independent autopsy was conducted by high-profile pathologist Michael Baden, who testified in the O.J. Simpson, Phil Spector and Drew Peterson murder trials.
Accounts of exactly what happened when Officer Darren Wilson stopped Brown while the teen was walking down a street vary widely.
Witnesses said they saw a scuffle between the officer and Brown at the police car before the young man was shot.
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Several witnesses said Brown raised his hands and was not attacking the officer.
Piaget Crenshaw said she was sitting in her home when she witnessed the shooting. She captured video of the aftermath, including images of Brown's body lying in the middle of the street.
"From it all initially happening, I knew this was not right," she told CNN's "New Day" on Monday.
"I knew the police shouldn't even have been chasing this young boy and firing at the same time. The fact that he got shot in the face, it was something that clicked in me, like no, somebody else needs to see this. This isn't right. I've got to record."
Crenshaw said Brown was running away from police and then turned around. She said that was when Brown was shot.
But police gave a different narrative, saying Brown struggled with the officer and reached for his weapon.
Though the officer has stayed out of the public spotlight, more than 22,000 people have endorsed the "I Support Officer Wilson" Facebook page.
U.S. Attorney General Eric Holder has approved another autopsy on Brown's body, the Justice Department said. That autopsy will be conducted by a federal medical examiner.