Beleaguered banking giant Wells Fargo said Friday it might uncover even more fake accounts, broadening a scandal that has dogged the company for nearly a year.

The third largest bank in the US said it was extending its internal probe to cover three additional years, which likely will uncover more fake savings and credit card accounts.

The company also revealed a fresh investigation by regulators into the bank's practice of charging fees to homeowners to maintain low interest rates on their residential mortgages for additional years.

As a result of continuing legal woes, Wells Fargo said the funds it has set aside to cover costs from legal actions swelled to $3.3 billion as of the end of June, up from $2 billion in the prior quarter.

Last year, the bank touched off a firestorm after admitting employees had opened millions of deposit and credit card accounts in customers' names without their knowledge in order to meet sales quotas.

The bank paid $185 million in fines, clawed back tens of millions in compensation from senior executives, and then-CEO John Stumpf stepped down after being publicly hammered by lawmakers.

In a quarterly report filed Friday to the US Securities and Exchange Commission, the bank said it had extended an internal review to cover seven years -- January 2011 to September 2016 -- rather than just four years.

As a result of widening the review, the bank expected "a significant increase" in the number of phony accounts identified, the report said. 

But any new payouts to customers should not affect the bank's financial position significantly, it said.

Separately, Wells Fargo also announced Friday it had settled a whistleblower lawsuit claiming it had improperly charged hidden fees to borrowers who were military veterans. The bank will pay the United States $108 million to settle the matter.

In a company-wide message published Friday, Wells Fargo CEO Tim Sloan told bank employees the bank was not yet out of the woods.

"To regain the trust we have lost, we must continue to be transparent with all our stakeholders and go beyond what has been asked of us by our regulators," Sloan said.

"No doubt, other work lies ahead."

Shares in Wells Fargo closed down more than one percent in New York on Friday.