Japanese and U.S. trade chiefs said Tuesday they have moved significantly closer in their bilateral talks for a broader Pacific free trade pact, but some problems still remain to be resolved.

Gaps over the biggest sticking points of agricultural imports and auto trade have been "substantially narrowed" ahead of their leaders' summit planned for next week, U.S. Trade Representative Michael Froman told reporters after wrapping up two days of negotiations with economic and fiscal policy minister Akira Amari.

But "continued work is needed" to ultimately cut a bilateral deal with Japan seen as vital for the 12-country Trans-Pacific Partnership agreement, Froman added.