UBS has agreed to buy Swiss banking giant Credit Suisse after increasing its offer to more than $2 billion, the Financial Times reported on Sunday, as authorities bid to stave off turmoil when the markets reopen.

Officials have been racing to rescue the 167-year-old bank, among the world's largest wealth managers, after a brutal week that saw the second- and third-largest U.S. bank failures in history. As one of 30 global banks seen as systemically important, any deal for Credit Suisse could ripple through global financial markets.

Swiss broadcaster SRF and other media reported that the government would hold an "important" press conference later on Sunday. They did not give any more details.

Credit Suisse shares lost a quarter of their value last week. The bank was forced to tap $54 billion in central bank funding as it tries to recover from scandals that have undermined the confidence of investors and clients.