New York police said on Tuesday that they had disbanded a deeply controversial and heavily criticised unit that sent undercover officers to spy on local Muslims.
Civil liberty groups welcomed the move, but called on New York authorities to address the damage exerted by unjustified spying based solely on religion.
The decision by America's largest police force is the first sign that new commissioner William Bratton is moving away from some of the post-9/11 intelligence-gathering practices of his predecessor, The New York Times reported.
Police said that the Zone Assessment Unit, previously known as the Demographics Unit, had been largely inactive since January and that personnel had now been reassigned to other duties within police intelligence.
"Understanding certain local demographics can be a useful factor when assessing information regarding potential threats coming to the attention of the New York City Police Department," it said in a statement.
"It has been determined that much of the same information previously gathered by the Zone Assessment Unit may be obtained through direct outreach by the NYPD to the communities concerned," it added.
Bill de Blasio, who in January took office as New York's first Democratic mayor in 20 years, welcomed the move.
"This reform is a critical step forward in easing tensions between the police and the communities they serve, so that our cops and our citizens can help one another go after the real bad guys," he said.
Civil liberty groups said the decision was an important first step but warned against its activities being transferred to other police units.
"We hope that the Demographics Unit's discriminatory activities will not be carried out by other parts of the NYPD," said Donna Lieberman, executive director of the New York Civil Liberties Union.
Hina Shamsi, director of the American Civil Liberties Union's National Security Project, said the disbanded unit was only one part of "a huge, discriminatory surveillance programme" that sent informants and police officers to spy on New York Muslims.
"We look forward to an end to all aspects of the bias-based policing that has stigmatised New York's Muslim communities and done them such great harm," she said.
Muslims in New York filed a lawsuit challenging the spy programme, arguing it stigmatised hundreds of thousands of innocent New Yorkers.
Police officials acknowledge that the program never generated a criminal lead, said the New York chapter of the Council on American-Islamic Relations.
"The damage of unconstitutional mass spying on people solely on the basis of their religion has already been carried out and must be addressed," said board president Ryan Mahoney.
"We need to hear from the mayor and NYPD officials that the policy itself has been ended and that the department will no longer apply mass surveillance or other forms of biased and predatory policing to any faith-based community."Watch: NYPD ends Muslim surveillance programme