Large US banks injected $30 billion in deposits into First Republic Bank on Thursday, swooping in to rescue the lender caught up in a widening crisis triggered by the collapse of two other mid-size US lenders over the past week.

Credit Suisse on Thursday said it was taking "decisive action" to strengthen its liquidity by borrowing up to $54 billion from the Swiss central bank after a slump in its shares intensified fears about a broader bank deposit crisis.