Wells Fargo Chief Executive Officer John Stumpf testifies Tuesday before the Senate Banking Committee. Stumpf was called to discuss an unauthorized account scandal.

WASHINGTON — Facing bipartisan outrage from a Senate panel over accusations of employee misconduct, Wells Fargo CEO John Stumpf appeared taken aback by the intensity of the verbal lashing. At a few points, he seemed flustered and stumbled a bit over his words. He bristled at assertions that the alleged opening of millions of customer accounts without their permission was a “scam.”

Peppered with criticism for nearly three hours at a hearing Tuesday, the CEO of the nation’s second-largest bank faced calls for his resignation from harshly critical senators. They pressed Stumpf about claims from regulators that Wells Fargo employees opened the unauthorized accounts, transferred customers’ money into them, and even signed people up for online banking in a feverish drive to meet sales targets.

Debit cards were issued and activated, as well as PINs created, without customers knowing, U.S. and California regulators said as they fined San Francisco-based Wells Fargo a combined $185 million earlier this month.

While partly political theater, members of the Senate Banking Committee showed rare bipartisanship in their condemnation of Wells Fargo, and weren’t satisfied by Stumpf’s show of contrition.

“Words that come like a San Francisco fog on little cat feet won’t cut it,” Sen. Sherrod Brown of Ohio, the panel’s top Democrat, told Stumpf. “These were not magically delivered `unwanted products.’ This was fraud; fraud that you did not find or fix quickly enough.”

Stumpf said he was “deeply sorry” that the bank failed to meet its responsibility to customers and didn’t act sooner to stem “this unacceptable activity.” He promised to assist affected customers.