As a grand jury deliberated Friday whether to indict a white police officer who fatally shot an unarmed black man in Ferguson, Mo., a growing chorus of top officials and community and religious leaders called for calm.
At least one school district canceled classes for Monday and Tuesday in anticipation of the imminent grand jury decision, and leaders including President Obama and U.S. Atty. Gen. Eric H. Holder Jr. again called for peace.
One of the more poignant calls for restraint came this week from Michael Brown Sr., whose 18-year-old son Michael died on Aug. 9 in a volley of shots fired by Officer Darren Wilson.
"No matter what the grand jury decides, I don't want my son's death to be in vain," he said in a video this week. "I want it to lead to incredible change, positive change, change that makes the St. Louis region better for everyone."
On Friday, Obama called for demonstrators in Ferguson to "keep protests peaceful."
Speaking with ABC News' George Stephanopoulos, Obama said, "This is a country that allows everybody to express their views, allows them to peacefully assemble, to protest actions they think are unjust, but using any event as an excuse for violence is contrary to rule of law and contrary to who we are."
Officials said Friday that they have been having discussions with some protest groups in an effort to minimize any difficulties once the grand jury decision is announced. Officials said there was unison on some general approaches, but no formal agreements.
"We have been dialoguing with various people in the community," Daniel Isom, director of the Missouri Department of Public Safety, told reporters. "I believe we have some understanding on how we'll act."
To demonstrators who want to be heard, he said: "We hear you. We are listening." To property owners: "We are going to protect your businesses" so they can keep communities strong.
"I do not expect the worst.... I expect the best of people," St. Louis County Executive Charlie A. Dooley said.
"This is not about violence," he said. "It is about peace."
Officials said they didn't know when the grand jury, which met Friday, would complete its deliberations. St. Louis Mayor Francis Slay said it probably would be soon.
The Jennings School District, which includes parts of Ferguson, canceled classes for Monday and Tuesday, a spokesman said. School is out the rest of the week because of the Thanksgiving holiday.
Also on Friday, in a video announcing new guidance for the way law enforcement handles protests, Holder called on demonstrators to remain nonviolent.
"Over the past few months, we've seen demonstrations and protests that have sought to bring attention to real and significant underlying issues involving police practices, implicit bias and pervasive community distrust," Holder said in the video, which was published on the Justice Department's website.
"Demonstrations like these have the potential to spark a sustained and positive national dialogue, to provide momentum to a necessary conversation, and to bring about critical reform," Holder said. "But history has also shown us that the most successful and enduring movements for change are those that adhere to non-aggression and nonviolence."
He said the new Justice Department guidelines include tips for "how to approach maintaining order during 1st Amendment-protected events," including avoiding "needless confrontation" and "choosing appropriate equipment and uniforms."
A few dozen protesters have gathered outside the Ferguson Police Department for the last two nights, and several have been arrested. On Thursday night, demonstrators blocked traffic outside the police station, prompting police to warn that the actions would result in arrest.
At least one police official recorded the demonstrators with a hand-held camera, as has been the case at several protests since at least October. St. Louis County Police spokesman Brian Schellman told the Los Angeles Times that facial-recognition technology is not being used to monitor demonstrators.
Law enforcement and public officials have repeatedly said they intend to balance public safety with respecting demonstrators' 1st Amendment rights. Descriptions in the St. Louis County Police arrest summaries have said that those who were arrested "exercised their constitutional rights, while also making insulting personal verbal attacks on officers."