Briefing Pacific trading partners on progress in U.S.-Japan trade talks is an important step in moving discussions on a 12-nation trade bloc to the next level, U.S. Trade Representative Michael Froman said on Wednesday.

The United States and Japan said after a leaders' summit last month they had found a path forward on access to Japan's farm and auto markets, but gave no details of what was agreed.

The stalemate between the two countries, the biggest economies in the Trans-Pacific Partnership, has held up progress on the wider trade agreement in recent months as other countries waited to see the outcome of the negotiations.

TPP negotiators, from countries including Canada, Australia, Mexico and Malaysia, will meet in Vietnam next week and Froman said the U.S.-Japan outcome was an important element in moving to the next stage of talks.

"We'll be briefing them on our discussions with Japan and they'll have their own discussions with Japan," he said in an interview with Reuters Insider television. "And that will be an important part of entering the next phase of the negotiations."

U.S. and Japanese officials have declined to confirm reports that the United States might allow Japan to keep tariffs on some products, such as rice, in exchange for lowering the tariff on U.S. beef imports to below 10 percent, stressing the complicated nature of the deal.

"Nothing's agreed to until everything's agreed to," Froman said, adding there was growing momentum toward closing the talks. "I think all of the parties around the table want to get this done." (Additional reporting by Leigh Thomas; Writing by Krista Hughes in Washington; Editing by James Dalgleish)