WASHINGTON – The FBI counterterrorism division's identification of a movement it calls "black identity extremists" is the latest addition to the list of protesters and dissidents the agency puts under the "domestic terrorism" umbrella.

But many national security experts say the designation doesn't describe a movement at all, let alone a terrorism threat. It's simply a label that allows the FBI to conduct additional surveillance on "basically anyone who's black and politically active," said Michael German, who left the FBI in 2004 and did undercover domestic terrorism work.

Critics are concerned that increasingly, it appears to be minorities and environmentalists who are being targeted.

While the practice of labeling certain protest groups as domestic terrorists is not unique to President Donald Trump's administration, Hina Shamsi, national security project director at the American Civil Liberties Union, said there's concern that "abusive and unjustified investigations" by the FBI are rising.

"We are worried that protesters are increasingly being labeled as terrorism threats," Shamsi said.

It's difficult to know for sure whether the Trump administration engages in the practice more often, however, because the FBI and other law enforcement entities rarely make that information available to the public. But critical rhetoric by the Justice Department and the White House also tends to inform FBI decisions, German said, and empowers those seeking to target those groups.

The problem, Shamsi said, is partly in the overly broad definition of domestic terrorism in the Patriot Act as a violation of U.S. or state criminal laws that is "dangerous to human life" and appears to be intended to "influence the ­policy of a government by intimidation or coercion."

Eighty-four members of Congress cited that intention to intimidate or coerce in a letter to the Justice Department this past week that asked whether the department had labeled Dakota Access pipeline protesters domestic terrorists. Calls and e-mails to multiple members of Congress who signed the letter were not returned.

Protests of the pipeline's construction led to the arrest of 761 people, most of them on misdemeanor charges, according to North Dakota authorities. Some protesters accused of setting fire to campsites and turning off safety valves in efforts to shut down the pipeline were charged with more serious crimes.

"Damaging pipeline infrastructure poses multiple risks to humans and the environment. When an individual burns a hole through a pipeline currently in operation, there is a high probability this could ignite the contents, killing not only the perpetrator but other innocent victims," said the letter, written by Rep. Ken Buck, R-Colo. "It also has the potential to cause property and environmental damage, as well as disrupt services to communities and consumers."

The FBI report that focused on black identity extremists, which was published in August and leaked to Foreign Policy in October, had interest groups questioning whether the designation has been used to target members of Black Lives Matter, though it never specifically mentions the group.

"The FBI defines black identity extremists as individuals who seek, wholly or in part, through unlawful acts of force or violence, in response to perceived racism and injustice in American society and some do so in furtherance of establishing a separate black homeland or autonomous black social institutions, communities or governing organizations within the United States," the leaked report says.

The report predicted it is "very likely" that black identity extremists would engage in "ideologically motivated, violent criminal activity" against police within a year.

It identified six attacks against police as examples of black identity extremism; but German, now a fellow at the liberal Brennan Center, said the logic in the report is deeply flawed.

"If you look at three of those cases, there's no ideology connecting them at all," German said. "The only commonality is that they're black."

"They're taking isolated incidents and turning it into a movement to justify increased surveillance," he continued. "It's throwing fuel on this argument of a war on police by black people, even though if you look at the numbers that's not the case."

There has been no significant change in the number of law enforcement deaths in recent years. So far in 2017, 107 police officers have been killed in the line of duty, according to the National Law Enforcement Officers Memorial Fund. In 2016, 135 officers died while on duty; 124 in 2015, 119 in 2014 and 177 in 2011. Viewed historically, the fluctuation is fairly typical, and the numbers are trending downward overall.