State Highway Patrol Captain Ron Johnson, placed in command of security in Ferguson last week after local police tactics that were criticised as overly harsh, said officers had come under "heavy gunfire" on Monday night but did not return it.
The predominantly African-American community of 21,000 people has been gripped by street protests punctuated by looting and clashes with police every night since the unarmed, 18-year-old Michael Brown was killed by a white police officer.
"Our innocent people need for a moment to go into their homes and not allow this criminal element to hide behind them," Johnson told reporters.
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