The government is planning to announce Friday the results of its preliminary negotiations with the United States on Japan joining the Trans-Pacific Partnership trade talks, sources said Thursday.

With the two sides already in agreement on key issues, including auto tariffs, U.S. President Barack Obama is expected to seek congressional approval for Japan's participation in the Pacific Rim free-trade talks. As Congress needs 90 days to give its approval, the earliest Japan could join the multilateral trade negotiations is expected to be July.

Japan expressed its commitment last month to join the talks and is waiting for approval by the 11 current members, of which Australia, Canada and New Zealand have yet to give the green light, while Peru, which expressed its support last year, is in the final stage of procedures to give its official consent.