The first night of a state-imposed curfew in Ferguson, Missouri, ended with tear gas and seven arrests, after police dressed in riot gear used armored vehicles to disperse defiant protesters who refused to leave a St. Louis suburb where a black, unarmed teen had been shot by a white police officer a week earlier.

Missouri State Highway Patrol Capt. Ron Johnson said protesters weren’t the reason for the escalated police reaction early Sunday morning after the midnight curfew took effect, but a report of people who had broken into a barbecue restaurant and a man who flashed a handgun in the street as armored vehicles approached the crowd of protesters.

Also overnight, a man was shot and critically wounded in the same area, but not by police; authorities were searching for the shooter. Someone also shot at a police car, officials said.

The protests have been going on since 18-year-old Michael Brown was shot and killed Aug. 9 by a white Ferguson officer, Darren Wilson. The death heightened racial tensions between the predominantly black community and mostly white Ferguson Police Department, leading to several run-ins between police and protesters and prompting Missouri’s governor to put the Highway Patrol in charge of security.

The Ferguson Police Department waited six days to publicly reveal the name of the officer and documents alleging Brown robbed a convenience store before he was killed, though Ferguson Police Chief Thomas Jackson said Wilson did not know Brown was a suspect when he encountered him walking in the street with a friend.

Gov. Jay Nixon declared a state of emergency in Ferguson on Saturday after protests turned violent the night before. In announcing the curfew, Nixon said that though many protesters were making themselves heard peacefully, the state would not allow looters to endanger the community.

“I am committed to making sure the forces of peace and justice prevail,” Nixon said during a news conference that was interrupted repeatedly by people objecting to the curfew and demanding that Wilson be charged with murder. “We must first have and maintain peace. This is a test. The eyes of the world are watching.”

It isn’t clear how many days curfew will be in effect. State statute gives the governor broad powers when he declares a state of emergency, but he hasn’t indicated that he plans to do anything other than imposing the curfew and empowering the state highway patrol to enforce it.

Meanwhile, Nixon said the U.S. Department of Justice is beefing up its civil rights investigation of the shooting.

Johnson, who is in charge of security in Ferguson, said 40 FBI agents were going door-to-door in the neighborhood starting Saturday, talking to people who might have seen or have information about the shooting.

Johnson said earlier Saturday that police would not enforce the curfew with armored trucks and tear gas but would communicate with protesters and give them ample opportunity to leave. Local officers faced strong criticism earlier in the week for their use of tear gas and rubber bullets against protesters.

But as the curfew deadline arrived early Sunday, remaining protesters refused to leave the area as officers spoke through a loudspeaker: “You are in violation of a state-imposed curfew. You must disperse immediately.”

As officers put on gas masks, a chant from the distant crowd emerged: “We have the right to assemble peacefully.”

A moment later, police began firing canisters into the crowd. Highway Patrol Spokesman Lt. John Hotz initially said police only used smoke, but later told The Associated Press they also used tear gas canisters.

“Obviously, we’re trying to give them every opportunity to comply with the curfew,” Hotz said.

On Saturday, some residents said it appeared the violent acts were being committed by people from other suburbs or states.

“Who would burn down their own backyard?” asked Rebecca McCloud, a local who works with the Sonshine Baptist Church in St. Louis. “These people aren’t from here. They came to burn down our city and leave.”

Wilson, the officer who shot Brown, is a six-year police veteran who had no previous complaints against him, Jackson has said. The Ferguson Police Department has refused to say anything about Wilson’s whereabouts, and Associated Press reporters were unable to contact him at any addresses or phone numbers listed under that name in the St. Louis area.

Wilson has been on paid administrative leave since the shooting. St. Louis County prosecutor Bob McCulloch said it could be weeks before the investigation wraps up.

(AP)