Alton Sterling Protesters Confronted With 'Militarized' Police, Suit Says

— -- The American Civil Liberties Union of Louisiana filed a civil lawsuit Wednesday against the Baton Rouge Police Department, along with other law enforcement and city and state officials, alleging that the rights of demonstrators protesting the shooting death of Alton Sterling were infringed upon.

"Police have repeatedly interfered with peaceful protests on public sidewalks and private property," according to the federal complaint, filed in Louisiana.

The civil rights action was filed by the ACLU and organizations whose members have participated in and witnessed protests in Baton Rouge following Sterling's death on July 5, the complaint stated. In addition to the ACLU, plaintiffs named in the civil lawsuit include North Baton Rouge Matters, the Black Youth Project 100, New Orleans' Workers' Center for Racial Justice and the Louisiana Chapter of the National Lawyers Guild.

"Plaintiffs have engaged in this peaceful speech, association, and protest on the streets, sidewalks, and medians of Baton Rouge—traditional public fora where individuals’ First Amendment rights are at their zenith," the complaint says. "Unfortunately, this exercise of constitutional rights has been met with a military-grade assault on protestors’ bodies and rights."

The suit also alleged that law enforcement officers have escalated peaceful situations, impeded protesters' entry or exit from demonstrations and threatened assault with chemical agents, including mace or pepper spray. The complaint also said police rounded demonstrators up in mass arrests and subjected them to physical and verbal abuse.

The lawsuit alleges that law enforcement's actions were designed to intimidate protesters and "deter the continued exercise of First Amendment rights."

"The right to be free from unreasonable seizure by the government is fundamental to the proper functioning of our criminal justice system," the complaint stated, which also noted that the Framers of the Constitution expressed "deep concern for personal security and their recognition of that potential law enforcement excesses."

On July 10, the complaint alleges that police confronted protesters, closing the streets and sidewalks and "brandishing" batons and assault rifles, "leaving protesters without access to that space to protest or leave the area." Police then grabbed and push some protesters to the ground and arresting them, including a reporter who was "clearly engaging in reporting activities," the lawsuit stated.

Sterling was shot at point-blank range by officers with the Baton Rouge Police Department after being tackled and physically restrained, according to the complaint. According to an affidavit for a search warrant, police shot him during a struggle after they say they saw him reach for a gun. Police have declined to comment about whether a gun was recovered.

Police also arrested demonstrators who had been invited to gather on private property after ordering them to leave, the complaint stated. Police tackled protesters to the ground, grabbing and pushing protesters standing in the doorway to the home, the documents stated.

The complaint alleges that individuals were maced or pepper sprayed for making comments or engaging in protest songs while in jail, and that those arrested were only fed one meal in 24 hours while in detention.

Representative for the City of Baton Rouge, Louisiana State Police and the East Baton Rouge Sheriff’s Department did not immediately respond to ABC news’ request for comment.

ABC News could not immediately reach the Baton Rouge Police Department for comment.

But the department's chief, Carl Dabadie, defended the response, according to the Associated Press, citing threats.

"We have been questioned repeatedly over the last several days about our show of force and why we have the tactics that we have. Well, this is the reason, because we had credible threats against the lives of law enforcement in this city," Dabadie said, according to the AP.

And on Tuesday, Gov. John Bel Edwards defended the police as well.

"We've had a police officer with teeth knocked out of his face because of a rock. If you don't have on riot gear, you have no defense against that sort of thing," the governor said, according to the AP.

"In light of what happened in Dallas, understanding that just one gunman can change the situation entirely, how do you in good conscience put police officers on the street without the ability to defend themselves?"