A key adviser to Prime Minister Shigeru Ishiba has held talks with senior White House officials and — likely most crucially for Japan — Republican lawmakers and others close to President-elect Donald Trump.

Akihisa Nagashima, who holds the post of special adviser to Ishiba, met with the lawmakers, officials and others during his visit to Washington from Wednesday through Sunday, according to the Foreign Ministry in Tokyo.

The visit to the U.S. comes on the heels of Ishiba’s aborted attempt to meet with Trump in the United States after the Japanese leader attended summits in South America earlier this month. Nagashima’s trip is expected to help pave the way for a future meeting between the two allies’ leaders.

During his visit, Nagashima — a Lower House lawmaker fluent in English and known in U.S. defense and foreign policy circles — met with Sen. William Hagerty, who served as Trump’s ambassador to Japan during his first term and had been mentioned as a possible nominee for secretary of state, as well as Rep. Michael McCaul, the powerful chair of the House Foreign Affairs Committee.

Nagashima also held talks with Sen. Rick Scott, another Trump ally, and Ken Weinstein, a Japan expert at the Hudson Institute think tank and the president-elect’s pick to replace Hagerty as U.S. ambassador to Japan during his first White House stint.

He also met with key Biden administration officials, including Deputy Secretary of State Kurt Campbell, who earlier served as the architect of the White House’s Asia policy.

During the spate of meetings, the talks were believed to have focused on foreign and security policy — including the U.S. nuclear umbrella, the joint development of defense equipment and the importance of maintaining trilateral security cooperation between the two and South Korea.

U.S.-Japan relations, especially in the defense and security spheres, have undergone a sea change in the years since Trump left the White House for the first time.

Tokyo, wary of China’s growing regional assertiveness, has ramped up defense spending and pledged to work even closer with Washington, with current U.S. President Joe Biden and then-Prime Minister Fumio Kishida using a summit earlier this year to laud the fresh heights the bilateral alliance had reached.

Trump’s stunning victory in the Nov. 5 presidential election, however, has left the Japanese government scrambling to lay the foundation for ties between Ishiba and the president-elect, especially amid fears that the incoming U.S. leader could again take a transactional approach to the alliance.

Nagashima said after the meetings that he was “confident” the U.S.-Japan alliance “can be further strengthened in a Washington that is now undergoing rapid change,” and that the two sides would continue to work on the timing of Ishiba and Trump’s first face-to-face meeting.