U.S. prosecutors criminally charged two former senior UBS traders in connection with an investigation into the bank's manipulation of the Libor benchmark rate, the Justice Department said on Wednesday.

A criminal complaint against former traders Tom Hayes and Roger Darin was unsealed in U.S. District Court in New York, the government said.

Both traders were charged with conspiracy, while Hayes was also charged with wire fraud and an antitrust violation, the government said.

Also on Wednesday the Swiss bank agreed to pay a $1.5 billion fine to U.S., UK and Swiss authorities to resolve related allegations.

(Reporting by David Ingram and Aruna Viswanatha; Editing by Jeffrey Benkoe)