NEW YORK (REUTERS) - New York state's attorney general on Tuesday launched an investigation into retailers Macy's Inc and Barneys New York Inc, where black customers complained they were stopped by police after making luxury purchases.

The city's feisty tabloids have nicknamed the practice "shop and frisk," a take-off on the controversial New York police crime-fighting tactic "stop and frisk," which critics contend amounts to racial profiling.

State Attorney General Eric Schneiderman gave the two department store chains until Friday to turn over information about their policies for detaining and questioning customers based on race.

But both department stores have fired back, denying any involvement in three of the four incidents which have ignited a firestorm of controversy.

"This was an operation of the New York City Police Department (NYPD)," Macy's spokesman Elina Kazan said in a statement, adding that store "personnel were not involved" in the incident.

Ms Kazan was not immediately available to respond to questions about a second black shopper's similar allegations about an April incident.

Barneys chief executive Mark Lee likewise said his employees had no part in either incident involving black customers.

"We believe that no Barneys employees were involved in those incidents," Mr Lee said after a meeting in Harlem with civil rights leader Al Sharpton and members of his National Action Network. "No one from Barneys brought them to the attention of our internal security and no one from Barneys reached out to external authorities." An NYPD spokesman did not respond to requests for comment on Mr Lee's remarks.

In letters to Mr Lee and Macy's chief stores officer Peter Sachse, released earlier on Tuesday, Mr Schneiderman's office said it is investigating a total of four complaints from black shoppers who said last week that at various times in the last eight months they were stopped by police after shopping at the two stores.

"The alleged repeated behavior of your employees raises troubling questions about your company's commitment to that ideal," wrote Ms Kristen Clarke, who heads the attorney general's civil rights bureau.

Tuesday's meeting between Mr Lee and civil rights leaders was called last Friday, as allegations against Macy's were first being reported.

Mr Sharpton and other leaders on Tuesday called for a summit with a "broad section" of city retail executives.

"This must be done immediately," Mr Sharpton said after meeting with Mr Lee. "Not weeks - days, hours. There needs to be a meeting."

SERIES OF COMPLAINTS

Barneys and the New York City Police Department were named in a lawsuit filed by Trayon Christian of Queens last week. The lawsuit said police had detained him in April for two hours after he bought a US$349 (S$432) Ferragamo belt, and they then released him without charging him.

Ms Kayla Phillips, a 21-year-old nursing school student, said she was surrounded by four undercover police officers in February after leaving Barneys with a US$2,500 Celine handbag she had purchased.

Two Macy's shoppers have made similar complaints. One was actor Rob Brown of HBO's Treme, who said he was handcuffed and held for an hour after purchasing a US$1,350 gold Movado watch for his mother, the Daily News said.

Macy's denied any involvement in the detention of Brown.

The fourth "shop and frisk" complaint was filed by Mr Art Palmer, 56, an exercise trainer from Brooklyn. He told the Daily News that he was surrounded by police, who demanded to see identification after he used his credit card to buy US$320 worth of Polo shirts and ties at Macy's in April.

New York's Civilian Complaint Review Board is investigating allegations of improper police stops of Mr Palmer and Ms Phillips, spokesman Linda Sachs said on Tuesday. Macy's has not yet responded to Mr Palmer's allegation.

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.

Crime statistics from the New York Police Department show grand larceny has risen 31.6 per cent over the past two years in the Midtown North precinct, which includes Macy's flagship store in Herald Square, and is up nearly 4 percent in the Upper East Side's 19th precinct, which includes Barneys New York.