NEW YORK (REUTERS) - A small group of demonstrators gathered at the Manhattan storefront of Barneys New York Inc on Wednesday to express outrage over black customers' complaints they were stopped by police after making luxury purchases.

The protest, organised by Brooklyn pastor the Reverend Clinton Miller, coincided with an investigation by the state attorney general into security practices at Barneys and fellow retailer Macy's Inc.

Four black shoppers have said they were detained in separate incidents at the two stores and later released without charges, touching off the latest racial controversy in a largely integrated city that nonetheless experiences frequent debates about prejudice and equality.

Fewer than two dozen demonstrators, some carrying signs, converged on the upscale department store in the early minutes of the protest.

"We are here today to say that Barneys is wrong because there is no one in the city of New York who is qualified to analyse a person's dress or manner to determine how much money they have and how capable they are to purchase something," said Mr Conrad Tillard, senior pastor at the Nazarene Congregational United Church of Christ.

Mr CMiller told the gathering that demonstrators stood in solidarity with the shoppers. A transit authority bus driver shouted: "Right on, all day long!" as he pumped a clenched fist in the open window of his moving bus.

"The disrespect that racial profiling does to us as a people will not be tolerated," said the Reverend Evelyn Manns, a pastor at Brooklyn Christian Center.

The two retailers and the New York Police Department traded blame on Tuesday over the incidents dubbed "shop-and-frisk" by tabloids after the controversial "stop and frisk" policing tactic aspects of which have been ruled unconstitutional for violating the rights of minorities.

Barneys and Macy's officials said police had acted on their own, without input from store staff, in choosing to stop shoppers who included Rob Brown, an actor in the HBO series Treme. In a deposition of former Macy's security guard Brenda Howard taken in June in connection with a lawsuit, the former guard said that security staffers at the department store are expected to make five shoplifting arrests a week.

That deposition was taken in connection with a lawsuit filed by a shopper who contends she was wrongly accused of shoplifting and detained by store security in 2010.

A Macy's spokesman did not immediately respond to a request for comment on the lawsuit.

On Tuesday, New York civil rights leader Al Sharpton met with Barneys chief executive officer Mark Lee, who said his employees had no part in two incidents at his stores.

"No one from Barneys brought them to the attention of our internal security," Lee said, "and no one from Barneys reached out to external authorities." Likewise, a Macy's spokesman denied that any staff member had a role in two incidents there.

Mr Brown said he was handcuffed in June after purchasing a US$1,350 (S$1,670) gold Movado watch for his mother, the Daily News reported. In the other incident, Mr Art Palmer, 56, an exercise trainer, said he was surrounded by police in April after using his credit card to buy US$320 worth of shirts and ties.

NYPD chief spokesman John McCarthy countered those claims, saying that in both incidents at Barneys and the case involving Brown at Macy's, officers were acting on information provided by store security. The Palmer case is still under investigation, Mr McCarthy said.

Barneys and the NYPD were named in a lawsuit filed last week by Mr Trayon Christian, a 19-year-old Queens student. The lawsuit said police had detained him in April for two hours after he bought a US$349 Ferragamo belt.

New York's Civilian Complaint Review Board is investigating allegations of improper police stops of Palmer and Brooklyn nursing school student Kayla Phillips, 21, who said she was surrounded by four undercover police officers in February when she left Barneys after purchasing a US$2,500 Celine handbag.

In 2005, Macy's paid US$600,000 to settle similar allegations that many of the chain's New York stores had targeted blacks and Latinos for particular scrutiny of theft, according to the New York Attorney General's office.