ZURICH (Reuters) - Switzerland has given around $51 million in formerly frozen assets to the United States in connection with a U.S. investigation into alleged corruption at oil company Petroleos de Venezuela S.A. (PDVSA), authorities said on Tuesday.

The transfer followed a December request to Switzerland from the United States to freeze $118 million in assets in connection with the U.S.'s PDVSA probe, the Swiss Federal Office of Justice (FOJ) said in an emailed statement.

"On 11 October 2016 the FOJ has ordered the handing over of the assets of about $51 million... The assets have been transferred about a week later to the U.S. authorities (Treasury Forfeiture Fund Suspense Account). The rest of the assets of $67 million still remain frozen," the FOJ said.

(Reporting by Joshua Franklin; Editing by Catherine Evans)