Japan and the United States have reached a broad agreement in trade negotiations, reports said Sunday, with the leaders of both countries expected to hold talks on the sidelines of the G7 summit.

"We saw a great progress," Japan's minister in charge of trade talks with the US, Toshimitsu Motegi, told reporters in Washington on Saturday after three days of extended bilateral negotiations with US Trade Representative Robert Lighthizer.

"This progress will be confirmed at the Japan-US summit" on the sidelines of the Group of Seven (G7) summit currently being held in France, where how to proceed further will be also discussed, Motegi said.

US President Donald Trump and Japanese Prime Minister Shinzo Abe enjoy close ties but the bullish US president has frequently claimed that Tokyo has an advantage in bilateral trade and has called for a "more fair" relationship.

Lighthizer and Motegi agreed Japan will place tariffs on US agricultural products up to levels that apply to members of the Trans-Pacific Partnership (TPP) pact, Japan's public broadcaster NHK and major Japanese national dailies reported.

Both sides agreed that Japan will cut tariffs on US beef and pork to the TPP levels, but will not set new quotas for butter and skim milk, NHK said, citing unnamed sources.

Japan has repeatedly said the extent of the opening up of its agricultural market would be within the concession it had made to members of the TPP pact.

After an abrupt US withdrawal, 11 countries circling the Pacific last year signed a slimmed-down version of the TPP trade deal, and the pact has been championed as an antidote to growing US protectionism under Trump.

The US president has since sparked fears of a trade war by levying steep tariffs and denouncing unfair trading practices.

The US will eliminate levies on a wide range of Japanese industrial products, but its tariffs on Japanese automobiles will be left for further negotiations as Trump sees the US trade deficit with Japan as a problem, NHK said.

Both sides hope to reach the final agreement by late September, reports said.