WASHINGTON (Kyodo) -- The top diplomats of Japan and the United States agreed Tuesday to elevate the bilateral relationship to "new heights" on all fronts and continue working multilaterally with like-minded countries such as the Philippines and South Korea, just a day after Donald Trump returned to the White House for a nonconsecutive second term.

After holding talks with U.S. Secretary of State Marco Rubio in Washington, Japanese Foreign Minister Takeshi Iwaya told reporters that they also agreed to continue making arrangements for a meeting between Prime Minister Shigeru Ishiba and Trump at an early date.

North Korea's nuclear and missile development programs as well as issues related to China were among the topics covered by Iwaya and Rubio, the Japanese Foreign Ministry said, adding they confirmed the further enhancement of the Japan-U.S. alliance's deterrence and response capabilities.

Iwaya said he explained to Rubio that Japan has been dramatically increasing its defense spending.

The U.S. State Department said the two discussed how their countries can cooperate to counter threats in the Indo-Pacific region and beyond, including "joint efforts against China's destabilizing actions."

In addition, Rubio and Iwaya discussed China's support for Russia's defense industrial base and Pyongyang's political and security alignment with Moscow, it said.

The Japanese ministry said they also agreed on the importance of addressing major challenges facing the region with "minilateral" cooperation involving three or four countries, such as Australia, the Philippines and South Korea, which Trump's predecessor Joe Biden aimed to strengthen during his term.

While discussing economic issues, Iwaya said he asked the top U.S. diplomat to dispel concerns among Japanese companies about investing in the United States.

The foreign minister's revelation came when he was asked whether Nippon Steel Corp.'s plan to acquire United States Steel Corp., blocked by Biden in early January, was on the agenda.

He and Japanese officials declined to say whether Nippon Steel's plan, also opposed by Trump, was discussed and a senior Japanese official said neither side touched on Trump's pledge to impose higher import tariffs.

During the meeting, which lasted about 30 minutes, Iwaya said he stressed that Japan had contributed to the U.S. economy as the largest investor for the last five years.

On Tuesday, Iwaya also met with Trump's national security adviser, Michael Waltz, covering similar ground, according to the ministry.

Iwaya reiterated that the Trump team's invitation for him to attend the presidential inauguration ceremony reflects the significance the new administration attaches to its relationship with Tokyo.

Japan is exploring a meeting between Ishiba and Trump in the United States as early as the first half of February, according to government sources.

Akihisa Nagashima, a special adviser to Ishiba, said on a Japanese TV program on Tuesday that the prime minister's team is preparing a package of investment proposals for his envisaged summit with Trump.

The aide said Japan is set to invest in the United States in areas such as artificial intelligence and nanotechnology, adding the ongoing preparations are to enable Tokyo to "take the initiative in making proposals."

During his U.S. Senate Foreign Relations Committee confirmation hearing last week, Rubio, a Florida senator and longtime China hawk, proved knowledgeable about global issues.

The confirmation process for Rubio, who was a senior member of both the chamber's foreign relations and intelligence committees, won bipartisan support and was one of the least contentious among Trump's Cabinet picks.

In his announcement of Rubio's nomination for secretary of state in mid-November, Trump called him a "true friend" of U.S. allies.

Trump's selection brought relief in Japan as Rubio has long advocated boosting cooperation with like-minded countries against mutual threats.

At the time of former Japanese Prime Minister Fumio Kishida's official visit to the U.S. capital in April last year, Rubio issued a statement saying, "Japan's role as a key ally in matters of security, intelligence and economic affairs cannot be overstated" as countries across the Indo-Pacific face greater threats from China and North Korea.

(By Takuya Karube)