President Donald Trump, accompanied by Japanese Prime Minister Shinzo Abe, left, speaks Sunday at a news conference at the G-7 summit in Biarritz, France, where they announced that the U.S. and Japan have agreed in principle on a new trade agreement. Credit: Andrew Harnik | AP

BIARRITZ, France — President Donald Trump said Sunday that he had reached a trade pact “in principle” with Japanese leader Shinzo Abe, in an apparent effort to gin up support for a tough-talk negotiating style that he says is bearing fruit.

Abe, however, said more work had to be done, and it was unclear what format the trade pact might ultimately take. Large trade agreements typically require congressional approval. Trump’s description of the trade deal made it sound as if it would be narrower in scale, though he didn’t provide many details.

Trump, talking up the deal’s potential effect, said it could be signed as soon as September.

“We’ve been working on a deal with Japan for a long time,” he said. “And we’ve agreed in principle … billions and billions of dollars.”

For more than a year, Trump has threatened to impose steep tariffs on Japan related to automobiles. He has said that Japan imports too many cars into the United States relative to what U.S. automakers send to China. But the trade pact under discussion does not appear to have much to do with cars.

U.S. Trade Rep. Robert Lighthizer told reporters that the deal would focus on “agriculture, industrial tariffs and digital trade.”

Trump has long tried to pressure other countries to buy more U.S. agricultural products, and he said this would be an element of the agreement with Japan.

“Perhaps you’d like to talk about” Japan’s plans to buy “hundreds of millions of dollars of corn that’s there, that you’ll be buying,” Trump told Abe in front of reporters.

Abe responded that there was need for Japanese companies to purchase corn but that “this will be done by the Japanese private sector.”

Larry Kudlow, one of Trump’s top economic advisers, said Sunday in an interview on CNN that the trade pact with Japan would have major positive implications for the United States. Precise details were not available, however.

Trump is facing increased pressure to show results from his long-standing effort to force other countries to make trade concessions, and Abe said more work was needed to complete the arrangement between the two countries.

“We still have some remaining work that has to be done at the working level,” Abe said.