A nonprofit advocacy group has filed a complaint against one of the biggest banks in the Charleston region, saying one of the lender's local branches discriminated against Hispanic mortgage applicants.

The National Fair Housing Alliance said a Bank of America office on James Island denied the borrowers' requests to speak with a loan officer or quoted a higher monthly payment and closing costs, compared to less-qualified prospective white borrowers.

The alliance said its undercover probe included sending "a series of Latino and white individuals" posing as loan applicants to the 540 Folly Road branch over several months to see whether they would be treated fairly.

The Washington, D.C.-based group said its undercover minority applicants had higher incomes, more money available for down payments and closing costs, and comparatively stronger employment profiles.

The last tests that found discriminatory practices were conducted Jan. 6, the group said in a complaint filed with the U.S. Department of Housing & Urban Development over alleged violations of the Fair Housing Act.

Bank spokesman said Terry Francisco said in a statement Tuesday that the company "is committed to fair and responsible lending and has a strong record of supporting all local communities, regardless of demographic makeup."

"Customers from minority communities account for one in every four home loans we originate," he said. "NFHA has not provided specific information about their allegations. If HUD pursues an investigation, we will fully cooperate with HUD."

The housing alliance filed a previous housing discrimination case against the Charlotte-based financial giant. In that 2012 complaint, it said the bank wasn't doing enough to maintain and resell homes it repossessed in minority neighborhoods in Charleston. HUD is still investigating the matter, the alliance said.