Wells Fargo employees used customers' private information to open unwanted checking accounts and credit cards in their names, resulting in unexpected fees and damaged credit scores, the city of Los Angeles claimed in a lawsuit filed late Monday.

The civil complaint says the largest U.S. mortgage lender encouraged employees to engage in "unfair, unlawful and fraudulent conduct" through a pervasive culture of high-pressure sales, the Los Angeles Times reported.

Branch employees had to sell a certain number of financial products each day, according to the complaint, even if there wasn't the foot traffic available to meet those quotas. The bank also encouraged employees to sell multiple products to family members and friends, according to the lawsuit.

Wells Fargo has blamed the problems on a few rogue employees who have been disciplined or fired and said it would defend itself.

"Wells Fargo's culture is focused on the best interests of its customers and creating a supportive, caring and ethical environment for our team members," the San Francisco-based bank said in a statement.

The Los Angeles investigation found only token efforts to prevent wrongdoing, according to court papers.

"Consumers should be entitled to expect that major financial institutions will treat them fairly," said Los Angeles city attorney Mike Feuer in a statement Tuesday. "Our lawsuit alleges that in Wells Fargo's push for growth the bank often elevated profit over its customers' legal rights."

The statement also invites Wells Fargo customers who believe they may have been victimized to contact the City Attorney's office.

Frank Ahn, who owns a convenience store and a coin-operated laundry in the San Fernando Valley, said he was repeatedly pressured over four years to open additional accounts at Wells Fargo. When he declined, the bank opened three savings accounts in his name anyway, Ahn said.

After he complained, the accounts were deleted, only to reappear again months later, he said.

"I just feel like every time I go to the branch, it's a battle with them," Ahn said at the news conference. "I've had more than 10 accounts at Wells Fargo. I only need one."

Feuer said the number of possible violations would be determined during a discovery process. If the suit prevails in Los Angeles County Superior Court, it would apply to county residents and possibly some customers farther away, he said.

Al Jazeera and wire services