Missouri Gov. Jay Nixon (D) speaks alongside representatives from the St. Louis, St. Louis County, and Missouri State police departments during a press conference called to discuss security concerns when the grand jury’s decision in the Michael Brown case is announced.  (Photo by Scott Olson/Getty Images)

Missouri Gov. Jay Nixon (D) declared a state of emergency Monday in anticipation of possible unrest following the announcement of findings of two separate criminal investigations into the death of Michael Brown, the unarmed black teenager killed by a Ferguson, Mo. police officer.

“Regardless of the outcomes of the federal and state criminal investigations, there is the possibility of expanded unrest,” Nixon said in an executive order. “The state of Missouri will be prepared to appropriately respond to any reaction to these announcements.”

Nixon said in the order he directed the Missouri State Highway Patrol, St. Louis County Police Department, and St. Louis Metropolitan Police Department to “operate as a Unified Command to protect civil rights” and put the St. Louis County Police Department in charge of security in Ferguson related to protest areas and demonstrations.

He also said the adjutant general of the Missouri could “call and order into active service such portions of the organized militia as he deems necessary to protect life and property.”

The state of emergency will expire in 30 days unless Nixon extends it.

St. Louis Mayor Francis Slay said the National Guard will arrive this week to assist city police in case violence erupts after a grand jury decides whether to indict the white police officer who fatally shot unarmed black teenager, Michael Brown. (Reuters)