Heavily armed men who refuse to identify themselves are patrolling the streets of Washington, DC. They were sent by the Bureau of Prisons.

• As part of President Donald Trump's crackdown on protests against racism, federal agents wearing no insignia have been patrolling the streets of Washington, DC.
• The officials have refused to identify themselves, but reporters have established that they're from the Bureau of Prisons.
• In a statement to news outlets, the bureau said the officials were not wearing identifying clothing "as they are serving a broader mission."
• Law-enforcement experts said that officials operating with no identifying insignia could evade accountability and spread confusion.

Heavily armed federal agents wearing no badges or identifying markings have been patrolling the streets of Washington, DC, this week as part of President Donald Trump's crackdown on protests against racism.

As part of Trump's bid to "dominate" protests that have swept US cities in the wake of the death of George Floyd, his administration has deployed a variety of military forces and federal law-enforcement officials.

The Secret Service agents, DC police officers, and US military members are usually easy to identify. But they have been joined by federal officials, many with no identifying information.

Wearing helmets and plain uniforms and carrying weapons or riot shields, the officials have refused to identify themselves when asked by reporters what branch of the federal government or military they represent.

They were seen on Tuesday and Wednesday. Washington, DC, had a curfew of 7 p.m. on Tuesday and 11 p.m. on Wednesday.

One official told Mother Jones' Dan Friedman that they were with the Department of Justice. That department oversees agencies like the FBI but has no direct enforcement personnel of its own.

Some people on social media discussing the identity of the mysterious officials compared them to the "little green men" Russian President Vladimir Putin sent to annex Crimea in 2014 who wore no insignia identifying them as members of the Russian military.

Some observers noticed that details on the officials' uniforms indicated that they were members of the Federal Bureau of Prisons.

The bureau said in a statement to news outlets that the officials were members of a crisis-management unit (like those involved in quelling prison riots).

The bureau said they were "not wearing BOP specific clothing as they are serving a broader mission."

Thaddeus Hoffmeister, a law professor at the University of Dayton, told The Hill that unlike members of the military, federal law-enforcement agents aren't always required to wear identifiable uniforms.

"As a general rule, members of the Army (Active Duty, National Guard, and Reserves) must wear an identifiable uniform," Hoffmeister said. "The folks you see without an identifiable uniform are primarily federal law enforcement who don't have the same requirements."

Law-enforcement experts said that it was extremely unusual for officers to be operating incognito and that people had no way of telling whether they were genuinely officials, which could generate confusion and chaos during unrest.

William Bratton, a former New York City police commissioner, told The Washington Post that the development was "very concerning."

"If those officers engage in any type of misbehavior during the time that they are there representing the federal government, how are you to identify them?" Bratton said. "What is the need for anonymity in controlling crowd demonstrations?"