Treasury Secretary Janet Yellen said she was "concerned" about Silicon Valley Bank depositors following the bank's collapse on Friday, but warned that investors wouldn't be get bailed out.

"Let me be clear that during the financial crisis, there were investors and owners of systemic large banks that were bailed out," Yellen told CBS News' "Face the Nation" on Sunday.

"The reforms that have been put in place means that we're not going to do that again. But we are concerned about depositors and are focused on trying to meet their needs."

Yellen said she'd been working with regulators all weekend after hearing from depositors to "design appropriate policies to address the situation," without giving further details.

She wanted to "emphasize" that US banks were safe and well-capitalized and that Americans "can have confidence in the safety and soundness of our bank system," adding that the crisis hadn't spread to other banks.

Yellen declined to comment when asked if customers with funds stuck in Silicon Valley Bank would be able to get their cash. "We're very aware of the problems that depositors will have. Many of them are small businesses, that employ people across the country. Of course, this is a significant concern."

The Federal Deposit Insurance Corporation (FDIC) took control of SVB Friday after California regulators shut it down when a failed $2.3 billion capital raise sent its stock crashing. The agency protects deposits of up to $250,000, but higher sums are at risk.