SEOUL - South Korea has upgraded its US alliance, said President Yoon Suk-yeol on Tuesday, as he briefed his Cabinet on a trip to the United States which pledged more South Korean insight into nuclear planning in the event of war with North Korea.

Mr Yoon held a summit with US President Joe Biden in Washington on April 26, as anxiety grows in South Korea over the North’s rapidly evolving nuclear and missile capabilities, and growing doubts that the US would risk its security to help its Asian ally.

Calls have been growing in South Korea, even among some senior members of Mr Yoon’s party, for the country to develop its own nuclear weapons. The US opposes that, assuring South Korea of protection under the US “nuclear umbrella”.

“The alliance has a nuclear-based upgrade, and has expanded to include supply chain, industrial and science and technology alliances,” Mr Yoon told his Cabinet.

Mr Yoon and Mr Biden agreed in a “Washington Declaration” to launch a nuclear consultative group to give South Korea more insight into, and a voice in, US contingency planning to deter and respond to any nuclear incident in the region.

They also agreed on new partnerships on supply chains and science and technology, including cyber security, electric vehicles and batteries, quantum technology, foreign assistance and economic investment.

Mr Yoon said the nuclear planning mechanism would be more effective than the North Atlantic Treaty Organisation’s Nuclear Planning Group by facilitating more frequent high-level bilateral discussions.

More US “strategic assets” would be regularly deployed to South Korea to maintain an “overwhelming retaliatory posture”, he said.

“We will build strong security, peace based on overwhelming strength, not the fake peace that relies on the good faith of the other party,” Mr Yoon said.

Some South Koreans, especially younger voters, have welcomed the summit’s achievements, including Mr Yoon’s speech to the US Congress and surprise singing at a White House state dinner.

But the opposition Democratic Party criticised a lack of progress on new US rules on electric vehicle subsidies, which South Korea fears could hurt its automakers.

A Democratic Party spokesman said Mr Yoon “only sang a song at the world’s most expensive karaoke” in return for billions of dollars of South Korean corporate investment.

Mr Yoon’s approval ratings rose slightly to 34.5 per cent, a poll released on Monday by Realmeter showed, marking their first rebound in four weeks. REUTERS