Amid LA protests, what officials say about the rules of force for National Guard, Marines

Their weapons are not loaded with ammunition, a U.S. official said.

That means they are tasked with protecting federal buildings and federal personnel only -- they will not patrol U.S. streets or try to detain protesters to assist police, the officials said.

While all the troops are carrying weapons, their guns will not have ammunition loaded in the chamber, officials said, but will carry ammunition as part of their regular uniforms that can be used in the rare case of needed self-defense.

They will not use rubber bullets or pepper spray, either, they said.

The rules of force the personnel are operating under call for them to de-escalate the situation as much as possible.

"The arrival of federal military forces in Los Angeles -- absent clear coordination -- presents a significant logistical and operational challenge for those of us charged with safeguarding this city," Los Angeles Police Department Chief Jim McDonnell said in a statement.

"The Los Angeles Police Department, alongside our mutual aid partners, has decades of experience managing large-scale public demonstrations, and we remain confident in our ability to do so professionally and effectively," he continued. "That said, our top priority is the safety of both the public and the officers on the ground. We are urging open and continuous lines of communication between all agencies to prevent confusion, avoid escalation, and ensure a coordinated, lawful, and orderly response during this critical time."

Retired Air Force Brig. Gen. Thomas Edmonds, a former vice commander of the Michigan Air National Guard, told ABC News, "If I were an on-scene commander in my previous life as a [National] Guard officer, I would immediately demand clarification, for my people's sake. I would be saying, so what, when do we use deadly force?"

Edmonds said it appears the military is "defining the mission as non-law enforcement."

"But they're putting them with law enforcement personnel as their 'protection.' And I don't see the distinction there between if I'm engaged in protecting a federal officer [or] federal building, [and if] I'm engaged in enforcing the law."

In total, there are 4,800 troops operating under Title 10 status: 4100 of them National Guard soldiers and 700 active-duty Marines.

The deployment of the 700 Marines was to ensure "adequate numbers of forces to provide continuous coverage" of the area, according to U.S. Northern Command.

The deployed force is known as "Task Force 51" and officials insist the troops have been trained in de-escalation, crowd control, and standing rules for the use of force.

ABC News' Alex Stone contributed to this report.