WASHINGTON — Officials in a little-known security unit within the Commerce Department conducted unauthorized surveillance and investigations into the agency’s employees that targeted people of Chinese and Middle Eastern descent, Senate investigators said in a new report.

The report, informed by more than two dozen whistleblowers and released this week by Sen. Roger Wicker, R-Miss., the top GOP member of the Commerce Committee, concluded that the Investigations and Threat Management Service functioned for more than a decade as “a rogue, unaccountable police force,” opening thousands of unauthorized investigations into department employees, often for specious reasons.

It found that the work of the office — consumed by concerns about rampant Chinese espionage in the United States — sometimes veered into racial profiling, and that its leaders used extreme tactics, such as sending masked agents to break into offices to search for incriminating evidence.

“Combating national security threats posed by China should be a priority for any agency, but that does not give the federal government a license to disregard the law,” Wicker said in a statement. “Abuse of authority and race-based targeting is unacceptable, especially in law enforcement.”

The unit, an internal security office inside the Commerce Department, became fixated on rooting out foreign espionage, according to the report, resorting to searching employees’ email accounts for certain phrases in Chinese and flagging “ethnic surnames” for background checks through secure intelligence databases. In some cases, its agents would covertly search employees’ offices wearing face masks and gloves, sometimes picking locks to gain entry.

Unit leaders often refused to close investigations into employees even after agents were unable to find incriminating evidence, at times leaving researchers or other employees in administrative limbo. Almost 2,000 cases remained open at the end of last year, Senate investigators said.

In recent years, American law enforcement officials have become increasingly concerned that China is expanding its spying efforts in the United States and using visiting Chinese scholars for intelligence-gathering purposes. The Senate report laid out how those fears fueled an aggressive, unauthorized counterespionage effort inside a department that houses scientific agencies staffed by researchers from around the world.

Under the Biden administration, department officials suspended the unit’s investigations and began an internal review of the program in April, a spokesperson said, adding that officials were examining Wicker’s report and took the allegations against the office “very seriously.”

This article originally appeared in The New York Times.