Prime Minister Shinzo Abe and U.S. President Donald Trump agreed Friday to further expand bilateral trade and investment as the two governments prepare to start negotiations toward a trade agreement as early as mid-January.

At a meeting in Buenos Aires, part of which was open to the media, Trump urged Abe to address the trade imbalance between the two countries “very quickly,” a sign that Washington will push Tokyo in the upcoming talks to cut the U.S. goods trade deficit.

Calling the deficit “massive” and “pretty substantial,” Trump said, “We hope that we’re going to be balancing it very quickly.”

Trump praised Japan’s purchases of F-35s and other U.S. fighter jets, a move that would significantly reduce the deficit.

“Japan is buying large amounts of our fighter jets, our F-35s and others, and we appreciate it very much,” he said. “They are really working with me on trying to balance our deficit.”

A senior Japanese official said the government had not decided on the new purchase of F-35s, but that the Defense Ministry is reviewing the nation’s whole fighter jet system for the future.

The coming trade talks will be led by Toshimitsu Motegi, the economic revitalization minister, and U.S. Trade Representative Robert Lighthizer.

Trump has been criticizing Japan over its hefty and chronic goods trade surplus with the United States. His administration is expected to push Japan for increased market access for automobiles and agriculture.

The U.S. goods trade deficit with Japan totaled $68.85 billion in 2017, the third-largest among countries with which the United States generated a trade deficit, according to U.S. Commerce Department data.

Meeting on the margins of the two-day Group of 20 summit, which runs through Saturday in Argentina’s capital, Trump told Abe that he looks forward to visiting Japan next year, apparently for an event related to the ascension of the new emperor.

“I’ll be going to a tremendous event in Japan,” the president said. “I was very honored to be invited.”

Abe congratulated Trump on a “historic victory” in the Nov. 6 congressional midterm elections, following a pattern in which world leaders have deployed flattery to forge better relations with the mercurial U.S. president.

Trump’s Republican Party lost control of the House of Representatives but slightly expanded its Senate majority.

Abe also said the Japan-U.S. alliance “has become more robust than ever” under Trump’s leadership.

The Japanese and U.S. leaders also discussed progress in the two countries’ cooperation on advancing a “Free and Open Indo-Pacific Strategy,” as well as next steps to implement their shared resolve to expand collaboration in areas such as energy and infrastructure, according to the White House.

The leaders reaffirmed close coordination bilaterally and trilaterally with South Korea in achieving the complete denuclearization of North Korea, according to the senior Japanese official.

They pledged to fully implement U.N. sanctions on North Korea in partnership with the international community so as to compel the country to give up its nuclear weapons and ballistic missiles.

In a separate meeting also involving Indian Prime Minister Narendra Modi, the three leaders agreed to advance the vision of an open Indo-Pacific, a move apparently aimed at countering China’s rising clout in the region.

It marked the first summit involving the three major democracies.

“As a treaty ally of Japan and major defense partner of India, the United States shares unique and exceptional relationships with both countries based on common democratic values,” the White House said.

“The three leaders reaffirmed the importance of the Free and Open Indo-Pacific vision for global stability and prosperity, and pledged to deepen trilateral cooperation,” it said.