Charleston, SC (WLTX) - Charleston city and community leaders are calling for calm in advance of two major trials.

The group held a news conference Monday afternoon in the city's downtown.

Jury selection began Monday in the trial of Michael Slager, the former North Charleston Police officer charged with murder in the shooting death of Walter Scott. Next week, jury selection begins in the federal trial of Dylann Roof, the man charged with killing nine people at Mother Emanuel AME Church in Charleston.

"We must let the justice system take its place," said Elder James Johnson, the South Carolina President of the National Action Network. "We do not know how this trial will turn out, but if it turns out guilty or not guilty, we must operate a safe city. We don't want anybody to get killed or hurt in this process."

He says there have been rumors that some people may come in from out of state to cause problems. "We would like for everyone to keep their ears and their eyes report anything that they may hear or see or people coming into our city," Johnson said. "We do not want outsiders coming into our city to speak for the people of Charleston, we can speak for ourselves."

Johnson says people should call 9-1-1 if they see suspicious behavior.

Charleston Mayor John Tecklenburg said the city opened its emergency operations center Monday, and it will remain as a resource to guide the town for the next several weeks while the trials takes place.

"It's truly an opportunity for the City of Charleston to continue to its role to show the world a community that's united in the belief that love conquers hate, a belief in our justice system, that it can work a belief in our community that we will come together and stay together no matter what challenge is before us," Tecklenburg said.

The leaders closed their meeting with a prayer.