Another US bank is seeking a financial lifeline as a crisis of confidence in the country's banking sector continues.

PacWest said it is considering its options after it said it had been approached by potential buyers and investors, as its share price plunged.

Confidence in the banking industry - especially mid-sized lenders - has been shaken by a series of failures.

Some banks have experienced difficulties because of a steady rise in interest rates.

Central banks have been lifting borrowing costs to combat rising prices, or inflation.

On Wednesday, the US Federal Reserve lifted the key interest rate again, this time to 5.25% which is the highest since 2007.

Unlike competitors which have collapsed in recent weeks, California's PacWest said it had not seen large numbers of customers rushing to take their money out.

But on Thursday evening, it admitted that it was considering its options after being "approached by several potential partners and investors". It said "discussions are ongoing".

The statement confirmed reports that sent PacWest's share price tumbling, with investors worried that it "will be the next domino to fall", according to analyst Susannah Streeter, at Hargreaves Lansdown.

Earlier this week, fellow Californian bank First Republic was rescued by US authorities which sold on billions of dollars worth of its loans and deposits to JP Morgan Chase.

First Republic is the third US mid-sized lender to fail within the past two months. Silicon Valley Bank was the first to fail in mid-March followed by New York's Signature Bank.

Turbulence has hit the share prices of other US banks including Western Alliance. Its stock dropped by 23% on Wednesday.

Zion, First Horizon and Comerica also each slumped more than 7%.

"Confidence in a financial institution is built over decades and destroyed in days," billionaire investor Bill Ackman wrote in a tweet. "As each domino falls, the next weakest bank begins to wobble."

Along with rate rises, US mid-sized banks including PacWest have been struggling due to investor fears over their loans to venture capitalists, who have heavily invested in technology firms.

The technology sector has been cutting jobs as firms struggle with a downturn in demand, high inflation and rising interest rates.

The spate of collapses has led to a focus on the issue by US lawmakers. On Thursday, the Senate Committee on Banking, Housing and Urban Affairs will have a hearing on "holding executives accountable after recent banking failures".