Japan's top trade negotiator is meeting with U.S. Trade Representative Michael Froman, seeking to resolve differences on autos and farm exports that are hindering progress toward a Pacific Rim trade deal.

Economy minister Akira Amari, Japan's top trade negotiator, described the talks, which began late Sunday as "extremely severe."

Amari said Monday that the two sides were still trying to resolve differences over removing trade barriers in key areas. Japan wants greater market opening for its exports of autos and auto parts. The U.S. hopes to export more rice, pork and other farm products to Japan.

The talks between Japan and the U.S. are part of negotiations among 12 nations participating in the U.S.-led Trans Pacific Partnership, which eventually aims to create a free trade zone in the Asia-Pacific region.