The report, released late Tuesday by the Brennan Center for Justice at New York University School of Law, calls for both Congress and the Obama administration to rein in investigatory powers granted to the FBI in 2008 by then-Attorney General Michael Mukasey.
The Obama White House has retained the powers, known as the Attorney General's Guidelines for Domestic FBI Operations, even though they were written during George W. Bush's administration.
The guidelines allow FBI agents, for example, to initiate surveillance on a person or group inside the United States without first opening a formal investigation and getting approval from a manager and without having probable cause.
"Both Congress and the Justice Department should act to ensure vigorous oversight of the guidelines' use," the report states. "There must be meaningful internal and external checks on the vast powers the FBI have been granted."
The report does not call for abolishing the guidelines but rather for more oversight to prevent abuses.
"The time to act is now--before the guidelines result in widespread and unwarranted intrusions into Americans' privacy, harmful religious and ethnic profiling, and the divergence of scarce resources to ineffective and indiscriminate collection of information," the report concluded.
The FBI could not be immediately reached for comment.
The law center hosted a panel discussion on Capitol Hill to release the report, at which participants stressed that the FBI should not operate with a blanket suspicion of any groups, especially the Muslim community in the United States.
"It seems to me that we've gotten into a set of laws, and now procedures, that are based on poorly examined practices," said Rep. Rush Holt, D-N.J.
At least for now, there does not appear to be an appetite in Congress to try to force the administration to make any changes to the guidelines. Holt noted, however, that lawmakers must consider reauthorizing three expiring provisions of the USA PATRIOT Act by February 28.
Emily Berman, author of the report and counsel in the Liberty and National Security Program at the Brennan Center for Justice, said she does not doubt that FBI agents are trying to act in good faith.
But she said broad investigative powers granted under the guidelines combined with pressure to prevent terrorist attacks could lead to "overbroad intelligence collection." Berman said that FBI agents should not be allowed to use surveillance techniques without first suspecting wrongdoing.
She added that agents should not be permitted to use race, religion, or ethnicity as the sole basis for suspicion.
The report received the most opposition from panelist Daveed Gartenstein-Ross, director of the Center for Terrorism Research at the Foundation for Defense of Democracies. He argued that FBI cases should be considered in context and that profiling based on race, religion, or ethnicity is sometimes necessary to help advance legitimate investigations.
He also said that the report was not prepared with input from law-enforcement agencies.