Visit by James Mattis comes despite suggestions by Donald Trump that he could cut US military presence in region

The new US secretary of defence, James Mattis, is to reassure Japan and South Korea of Washington’s commitment to the security of the volatile Asia-Pacific region, despite suggestions by Donald Trump that he was ready to scale down the US’s military presence there.



Mattis, a retired Marine general, will reaffirm America’s role in strengthening security ties with its two strongest allies in the region when he visits South Korea on Tuesday and Japan the following day.

“The trip will underscore the commitment of the United States to our enduring alliances to Japan and the Republic of Korea, and further strengthen US-Japan-Republic of Korea security cooperation,” the Pentagon spokesman, Jeff Davis, said.

Trump rattled nerves in Tokyo and Seoul during the presidential election campaign when he suggested he would withdraw tens of thousands of troops from Japan and South Korea unless their governments paid more to maintain US forces based there.

In an interview with Fox News last April, he also intimated that the two countries should be able to develop independent nuclear deterrents – a move that would trigger a potentially catastrophic Asia-Pacific arms race.

South Korea hosts about 28,500 US troops, mainly along its heavily armed border with North Korea. Japan is home to about 47,000 US military personnel, more than half of whom are based on the southern island of Okinawa, where a row over the construction of an offshore runway for use by the marines has fuelled anti-US sentiment.

Japanese officials have pointed out that Japan contributes almost 75% of the total cost of hosting US troops in the country. “The Japan-US alliance is not a mechanism from which only one of the countries benefits,” the chief cabinet secretary, Yoshihide Suga, said earlier this month. “We believe the costs are being appropriately shared between Japan and the United States.”

Japan and South Korea are eager to build on the close military ties they enjoyed under Barack Obama, amid rising tensions over North Korea’s nuclear weapons programme and China’s military buildup in the South China Sea.

In his new year’s speech, North Korea’s leader Kim Jong-un boasted that the country was preparing to test-launch an intercontinental ballistic missile “soon” – a claim that has been supported by South Korean intelligence officials.

Mattis will visit Japan and South Korea amid rising tensions over Chinese island-building in disputed parts of the South China Sea.

China, meanwhile, has warned the US to “speak and act cautiously” after the White House said it would oppose Chinese attempts to “take over” the South China Sea. The foreign ministry in Beijing urged Washington to avoid doing anything to “harm the peace and stability” of the strategic waterway.

This month, Chinese state-controlled media said Beijing would “take off the gloves” if Trump followed through with a promise to abandon the US policy of recognising that Taiwan is part of “one China”.

Mattis has been more emphatic than Trump in affirming the new administration’s commitment to its military alliances. He described “the Pacific theatre” as a priority, and some analysts expect an anticipated rise in defence spending under Trump to strengthen the US military’s presence in the Asia-Pacific.

On Monday, Mattis reiterated America’s “unshakeable commitment” to Nato. That contrasts with earlier comments by Trump, who described the organisation as “obsolete” for being ill-equipped to fight international terrorism, and criticised most of its members for not paying their fair share towards the alliance.

During his senate confirmation hearings last week, Mattis also acknowledged that it was in the US’s interest to preserve its alliances with South Korea and Japan. “The United States is stronger when we uphold our treaty obligations,” he said, but added: “We expect our allies and partners to uphold their obligations as well”.

Though dismayed by Trump’s decision to pull the US out of the Trans-Pacific Partnership free trade deal, Japan’s prime minister, Shinzō Abe, appears to have convinced the president that Japan should figure prominently on his security agenda.

Abe was the first foreign leader to meet Trump after his election victory in November, and the two leaders are reportedly preparing to hold a summit in Washington in the first half of next month.