U.S. Defense Secretary James Mattis (3rd L) and his South Korean counterpart Han Min-Koo (L) inspect an honour guard at the Defense Ministry in Seoul, South Korea, February 3, 2017. Oh Dae-il/News1 via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. SOUTH KOREA OUT. FOR EDITORIAL USE ONLY. NO RESALES. NO ARCHIVE.
James Mattis, right, and his South Korean counterpart Han Min-koo inspect an honour guard on Friday in Seoul © Reuters

James Mattis warned Pyongyang that the US would respond to any use of nuclear weapons with “overwhelming” force during a visit to South Korea and Japan in which he reassured the two nations on their alliances with Washington.

Speaking in Seoul one week after the White House launched a North Korea policy review, the new US defence secretary said Pyongyang continued to engage in “threatening rhetoric and behaviour” with missile launches and its nuclear weapons programme.

To reassure South Korea and Japan that President Donald Trump and his administration were supportive of the alliances — despite campaign bluster that suggested otherwise — Mr Mattis said the US commitment to defending them was “ironclad”.

“Any attack on the United States, or our allies, will be defeated, and any use of nuclear weapons would be met with a response that would be effective and overwhelming,” Mr Mattis said at the South Korean defence ministry.

Speaking later in Tokyo, Mr Mattis told Japanese prime minister Shinzo Abe that the US stood “100 per cent shoulder-to-shoulder with you and the Japanese people”.

Mr Trump sparked concern in Japan and South Korea during the campaign by suggesting that he might withdraw US troops from the allies’ territory unless they assumed more of the financial burden.

Mr Mattis was making his first overseas trip since his confirmation as defence secretary. Mr Abe welcomed his early visit to Japan as evidence that the Trump administration was committed to what he described as an “unwavering alliance”.

Frank Jannuzi, director of the Mansfield Foundation in Washington, said Japan and South Korea were “not naive” about the changed political situation in the US.

“Both understand that they are dealing with an unprecedented change in Washington to an . . . anti-establishment administration so they need to reset their expectations about the reliability. And I don’t think that is damage that is easy to repair . . . From here on out, there will be a new awareness in Seoul and Tokyo that the US is not quite the partner that they thought we were.”

Washington shares Tokyo and Seoul’s anxiety over North Korea’s nuclear threat as it edges closer to being able to reach the US with a nuclear-armed missile.

Pyongyang took a defiant stance on Friday, blaming US actions for its nuclear weapons programme — which it vowed to continue — and demanding the withdrawal of the 28,000 American troops stationed in South Korea and the scrapping of joint annual military exercises with the country.

The South Korean government said on Friday that Kim Jong Un, the North Korean dictator, had sacked his top security official, in another sign of turbulence. The minister of state security was a close aide of Mr Kim, who defectors and experts say has ramped up the brutal policies of his father and grandfather, the nation’s previous leaders. Last week, a prominent North Korean defector in Seoul claimed that the country’s upper echelons were turning against Mr Kim.

During his visit to South Korea, Mr Mattis reconfirmed that the Pentagon wanted to proceed with the deployment of a Terminal High Altitude Area Defence (Thaad) missile shield on the Korean peninsula.

However, on Friday, Lotte, a South Korean conglomerate, said it had indefinitely deferred a decision on a deal to swap land wanted by the government to host the system. The company’s operations in China have come under scrutiny from Beijing following news that the group would trade the land. China strongly opposes the Thaad programme, which it fears would undermine its own nuclear deterrent and that the installation’s powerful radar system could be used to spy on China.

While Mr Mattis has spent two days reassuring South Korea and Japan, the Japanese government would like him to make a statement that the disputed Senkaku Islands, which are known as the Diaoyu in China, and are covered by Article 5 of the US-Japan security treaty, which obliges the US to fight in their defence.

Barack Obama restated that policy, which dates back to 1972, when he visited Japan in 2014. But Japan likes to hear the pledge afresh from each new administration.

Additional reporting by Robin Harding, Song Jung-a and Kang Buseong

Follow Demetri Sevastopulo on Twitter: @dimi

Get alerts on US foreign policy when a new story is published

Copyright The Financial Times Limited 2019. All rights reserved.
Reuse this content (opens in new window)

Follow the topics in this article