Senior Pentagon officials are concerned about the militarized appearance of police and law enforcement officers

The official said that one of the Pentagon's concerns is that law enforcement officers are wearing uniforms and using equipment that bear a striking resemblance to those worn by US troops in combat.

"Civilian law enforcement is sometimes dressed like the military. It confuses people. The public is led to believe that some of these civilian law enforcement units are military units instead -- they are not. We don't want that confusion," the official said.

The official added that the issue of police militarization "could" soon be discussed with the Justice Department as part of a proposed overall review of how the military works with law enforcement, which Esper recently broached with Attorney General William Barr.

Esper's concern is not limited to those law enforcement officers that fall under the Justice Department, and applies to a variety of police and other law enforcement groups, the official said.

Defense officials believe that the confusion led many to believe that the US military and National Guard were responsible for forcibly clearing peaceful protesters from Lafayette Park earlier this month, an action that drew condemnation from several former senior defense officials, some of whom accused the Trump administration of using the military to violate the constitutional rights of protesters.

While there were National Guard troops present, those forces remained in fixed positions and did not advance on the protesters, a task carried out by civilian law enforcement personnel using tear gas and other non-lethal weapons.

"If civilian law enforcement is going to go out there and push the crowds back and start using force, we don't want them looking like us. That's not us," the senior defense official said.

"In fact, in Lafayette Park our folks never moved. They stood in place. It was law enforcement moving forward. But in some places, some of the pictures have folks in green. And no matter what you do, it looks like military," the official added.

The Department of Justice declined to comment.

Esper and the chairman of the Joint Chiefs of Staff Gen. Mark Milley both acknowledged the problematic nature of their appearance alongside President Donald Trump in a photo-op after the protesters were cleared from Lafayette Park, with Esper telling reporters last month "I was not aware of a photo-op was happening," adding that he tried "to stay out of situations that may appear political, and sometimes I'm successful with doing that, and sometimes I'm not as successful."

Milley apologized and called the move a "mistake" saying his presence "created a perception of the military involved in domestic politics."

Some lawmakers have long criticized what they say is the militarization of police forces in the US, and many have called for an end to a long-existing program that transfers surplus military equipment such as armored vehicles, firearms, and night vision goggles to civilian law enforcement agencies.

Under the program, known as the 1033 Program or Law Enforcement Support Office, law enforcement agencies do not pay for the surplus equipment but are required to pay for shipping the items as well as potential storage costs.

Some 8,200 federal, state and local law enforcement agencies from 49 states and four US territories participate in the program which was established by law in 1997.

During a 1997 Los Angeles shootout, police officers saw themselves outgunned by body armor clad bank robbers armed with AK-47s and armor piercing ammunition during the infamous north Hollywood shootout.

The Defense Department has sent at least $760 million worth of surplus military equipment to law enforcement agencies around the country since August 2017, when President Trump lifted some restrictions imposed on those transfers by his predecessor Barack Obama, a recent CNN analysis of federal data found.

The Obama era restrictions had prohibited the transfer of tracked armored vehicles and bayonets.

While the equipment is provided by the Pentagon's Defense Logistics Agency, responsibility for verifying whether law enforcement agencies actually need the extra military kit sits with a state coordinator typically appointed by a governor.

It remains to be seen whether the Pentagon's concerns about the militarized appearance of police will result in any curbs being placed on the program as the transfer of military uniforms, body armor and helmets is already prohibited. The Pentagon could decide to block the transfer of military vehicles and weaponry but it's up to police forces and law enforcement agencies to decide on the appearance of officers. Any change in policy on that would need the Department of Justice to act, which is why Esper raised the issue with Barr.

Other military equipment that is prohibited from being transferred to law enforcement agencies includes armed vehicles such as tanks, Bradley fighting vehicles, and armed drones, "crew served/large caliber (.50 cal or greater) weapons and ammunition; military uniforms; body armor; Kevlar helmets; and explosives or pyrotechnics of any kind," according to the Defense Logistics Agency.

"The LESO/1033 Program is just one way for law enforcement agencies to obtain military sourced equipment," the Defense Logistics Agency statement added.

CORRECTION: This story and headline have been corrected to reflect that, while senior Pentagon officials are concerned about the militarized appearance of law enforcement officers, Esper has not raised the issue with Barr.