Missouri Gov. Jay Nixon. (David Carson/St. Louis Post-Dispatch via AP)

As the grand jury decision looms regarding the August shooting of Michael Brown, an announcement that will likely be followed by renewed protests on Ferguson’s streets, authorities said they want to allow people to protest peacefully but stressed that they were preparing to respond to any violence.

“Our dual pillars here are safety and speech,” Missouri Gov. Jay Nixon (D) said during a news conference Tuesday afternoon.

Nixon said that law enforcement officers have extensively prepared for the response to the grand jury decision. State and local agencies would coordinate through a unified command, with the Missouri National Guard remaining available as a “contingency plan” if necessary, he said.

A grand jury in St. Louis County is deciding whether to charge Darren Wilson, a Ferguson police officer, in the shooting and killing of Brown, an unarmed 18-year-old. The shooting on Aug. 9 sparked a series of heated protests that eventually garnered international attention as throngs of angry protesters faced off each night with heavily armed police officers wielding tear gas. The police response was criticized, with President Obama calling the scenes disturbing and Attorney General Eric H. Holder Jr. expressing concerns regarding the use of military equipment.

The National Guard was eventually called on as the nightly clashes persisted, one of several steps that Nixon took to try and stave off additional unrest. In the days after Brown’s death, Nixon announced a curfew (which was dropped two days later) and put the Missouri Highway Patrol in charge of securing Ferguson.

While Nixon discussed the importance of letting people protest peacefully and said Tuesday that most people who planned to protest were going to be respectful, his introductory remarks heavily focused on maintaining order during the expected response. Nixon said that his primary job is ensuring public safety and said peaceful protests in the days after Brown’s death “were marred by senseless acts of violence and destruction,” pointing to fires that were set and gunshots fired during the unrest.

“That ugliness was not representative of Missouri and it cannot he repeated,” he said. Nixon also promised Tuesday that authorities were making progress on the larger issues raised by the shooting.

It is still unclear when the decision on a possible indictment will be announced, Nixon said. St. Louis County Prosecuting Attorney Robert McCulloch said a day earlier that the decision would come in mid-to-late November, but he did not offer a specific date. The grand jury has until January to make a decision on possible charges, but McCulloch has pointed multiple times to a decision coming this month.

Few in the St. Louis area are expecting that Wilson will be charged, so residents and activists have been talking with police about ways to allow demonstrations while preventing any violence. Protests have continued since the height of the response to Brown’s death, with many activists focusing on removing McCulloch from the case.

Nixon would not discuss the role of the Ferguson Police Department during his Tuesday news conference, and that department was not among the agencies represented or highlighted as part of the planned police response. Thomas Jackson, the Ferguson police chief, is expected to leave his post, according to law enforcement officials.

The Justice Department is conducting a larger investigation into the policing practices of the Ferguson Police Department. In addition, investigators are also carrying out a civil rights investigation, though officials said that it is unlikely this investigation will result in any charges.

Before Nixon spoke on Tuesday, activists issued statements dismissing his plans. “We have proven we can peacefully assemble and function at a protest, can the police say the same?” community organizer Damon Davis said in a statement.

The Don’t Shoot Coalition, which is made up of about 50 groups formed after Brown’s shooting, last week vowed to promote a peaceful response while also calling on police to give protesters enough space.

[This post has been updated. First published: 3:43 p.m. Last updated: 4:19 p.m.]