“In Japan and South Korea, sensitive issues are being raised publicly, including whether to allow nuclear weapons to be deployed on their soil, or even go a step further and build capabilities to develop such weapons,” Lee said in a keynote speech at Nikkei’s Future of Asia conference in Tokyo.

“But if we only look at regional security from the perspective of individual nations, we may end up with an arms race, and an unstable outcome.” He added that countries “must therefore also work together to strengthen their collective security”.

Lee also highlighted the “difficult relations” between the US and China. “If US-China relations continue on this path, it will lead to further bifurcation of technology and splitting of supply chains, or even worse unintended consequences.”

The Future of Asia is Nikkei’s flagship annual conference, with top leaders from across the region taking the stage to address Asia’s role in a divided world.

The annual two-day event will also feature speeches from Malaysian prime minister Ismail Sabri Yaakob and the standing deputy prime minister of Vietnam.

Other political and business leaders from across the region, including Thailand and Sri Lanka, are scheduled to address attendees on the first day. Japanese prime minister Fumio Kishida will give a speech at a dinner.

The day will also feature a panel discussion on how entrepreneurs from Asia are going global with new business models and technologies.

The ripple effects of Russia’s invasion of Ukraine in February are still being felt across Asia. The Friday sessions will start with a panel discussion by experts on how Russia’s invasion will impact US-China relations.

That will be followed by presentations from former prime ministers of Australia and Malaysia. Day Two will also feature addresses from Bangladeshi prime minister Sheikh Hasina and India’s foreign minister, S Jaishankar.