The United States and Japan signed an agreement on Tuesday for "securing" supplies of critical minerals and rare earths, the White House said, as President Donald Trump visited Tokyo.

The deal comes as the United States tries to boost access to critical minerals with the dominant supplier, China, tightening controls on rare earths.

The objective of the deal is "to assist both countries in achieving resilience and security of critical minerals and rare earths supply chains", the White House said in a statement.

It said the United States and Japan would "jointly identify projects of interest to address gaps in supply chains for critical minerals and rare earths, including derivative products such as permanent magnets, batteries, catalysts and optical materials".

The two countries "intend to mobilise government and private sector support," it added. Earlier on his tour of Asia, Trump and Malaysian Prime Minister Anwar Ibrahim signed a trade agreement, boosting US access to critical minerals.

The deal came as Trump began one of his busiest days of his Asia trip by warmly greeting the new Japanese prime minister Sanae Takaichi with plans to later speak to US troops aboard an aircraft carrier and mingle with business leaders.

Although Trump is visiting one of America’s most steadfast allies in Asia, there’s no shortage of uncertainty while he’s there. Takaichi, who became the country’s first female prime minister only days ago, must solidify her relationship with Trump while defending her country’s economic interests. Trump is trying to nail down US$550 billion in Japanese investment as part of a trade agreement.

As Trump and Takaichi met on Tuesday, they shook hands and he paid her a compliment: “That’s a very strong handshake."

Takaichi used her early remarks to mention former Japanese prime minister Shinzo Abe, her arch-conservative mentor who forged a strong bond with Trump during his first term through their shared interest of golf. “As a matter of fact, prime minister Abe often told me about your dynamic diplomacy,” she said.

Trump called her role as Japan's first woman prime minister as a “big deal,” putting an emphasis on the US commitment to Japan. While the president in the past has publicly scolded his foreign counterparts, he had nothing but praise for Takaichi.

“Anything I can do to help Japan, we will be there,” Trump said. “We are an ally at the strongest level.”

White House Press Secretary Caroline Leavitt said on Tuesday Takaichi will nominate Trump for the Nobel Peace Prize. (Agencies/Xinhua)