The civil rights activist Reverend Al Sharpton is threatening to boycott the luxury New York retailer Barneys over allegations by shoppers that they were racially profiled there.

"We've gone from stop and frisk to shop and frisk, and we are not going to take it," Sharpton said on Saturday, adding that black New Yorkers "are not going to live in a town where our money is considered suspect and everyone else's money is respected".

Two black Barneys customers, Trayon Christian and Kayla Phillips, said this week they were detained by police after making expensive purchases. Christian sued Barneys, saying he was accused of fraud after using his debit card to buy a $349 Ferragamo belt in April.

According to a lawsuit filed on Monday, after leaving Barneys, Christian was accosted by undercover NYPD officers, who said someone at the store had raised concerns over the sale. The lawsuit said he showed the receipt from the purchase, the debit card he used to make it and identification to the officers, but he was told the identification was false and "that he could not afford to make such an expensive purchase".

The lawsuit said Christian was held at a precinct in a cell for more than two hours before being released with no charges filed against him. It said the incident was due to "discrimination based on plaintiff's race and age as he was a young black American male".

The CEO of Barneys, Mark Lee, offered his "sincere regret and deepest apologies". Barneys said on Thursday it had retained a civil rights expert to help review its procedures. In a statement, the retailer said: "Barneys New York has zero tolerance for any form of discrimination and we stand by our long history in support of all human rights."

Sharpton vowed to put shopping at Barneys "on hold" if the retailer fails to respond adequately to the allegations.

Macy's was also hit with a lawsuit alleging racial profiling this week.

A black actor on the HBO drama series Treme said on Friday that he was stopped by police because of his race while shopping at Macy's flagship Manhattan store. Robert Brown said in his lawsuit that he was detained by police on 8 June after employees contacted authorities about possible credit card fraud.

Macy's did not comment on the litigation but said in a statement it was investigating. © Guardian News and Media 2013