TOKYO - Japan and Nato said on Tuesday they would strengthen their ties, as Russia’s invasion of Ukraine and Moscow’s growing military cooperation with China have created the most tense security environment since World War II.

The comments came during Nato chief Jens Stoltenberg’s trip to Japan, following a visit to South Korea during which he urged Seoul to increase its military support for Ukraine and gave similar warnings about rising tension with China.

“The world is at a historical inflection point in the most severe and complex security environment since the end of World War II,” said Mr Stoltenberg and Japanese Prime Minister Fumio Kishida in a joint statement.

They also raised concerns about Russia’s nuclear threats, joint military drills between Russia and China near Japan, and North Korea’s development of nuclear weapons.

Mr Stoltenberg told reporters that a Russian victory in Ukraine would embolden China at a time when it is building up its military, “bullying its neighbours and threatening Taiwan”.

“This war is not just a European crisis, but a challenge to the world order,” he added.

“Beijing is watching closely and learning lessons that may influence its future decisions. What is happening in Europe today could happen in East Asia tomorrow.”

China’s Foreign Ministry did not immediately respond to a request for comment on Mr Stoltenberg’s latest remarks.

Responding to similar comments Mr Stoltenberg made during his Seoul visit, China on Monday said it was a partner to countries, not a challenge, and that it did not threaten any nation’s interests or security.

While Nato groups 30 countries in Europe and North America, Mr Stoltenberg has said its members are affected by global threats.

Mr Kishida and South Korean President Yoon Suk-yeol became the first leaders from their countries to attend a Nato summit in 2022, joining as observers.

China has previously criticised Nato’s efforts to expand its alliances in Asia.

Russia, which calls its invasion of Ukraine a “special operation”, has repeatedly cast Nato’s expansion as a threat to its security.

In December, Japan unveiled sweeping plans to beef up its defence capabilities, changes once unthinkable for a pacifist country that will make it the third-biggest military spender after the United States and China.

Bolstering its cooperation with Nato in areas from maritime security and arms control to cyberspace and disinformation will further help to respond to the changing strategic environment, Mr Stoltenberg and Mr Kishida said in their statement.

The meeting comes as Japan prepares to host the annual Group of Seven summit in May, where Russia’s invasion of Ukraine is expected to be a major topic of discussion.

Mr Kishida is considering visiting Kyiv in February to reinforce his support for Ukraine in the conflict, domestic media has reported.

“The war in Ukraine matters for all of us, and therefore we’re also very grateful for the support that Japan is providing, using also the planes and the cargo capabilities,” said Mr Stoltenberg during a brief speech after surveying the Japanese Self-Defence Forces’ Iruma Air Base.

Ukraine has been asking its allies in the West for more advanced weaponry as it braces itself for fresh clashes with Russia as winter recedes.

This week, Lithuanian President Gitanas Nauseda said Nato’s partners must cross yet another red line and send fighter jets and long-range missiles to Ukraine.

“The turning point is about to happen,” he said.

Ukraine is already set to receive main battle tanks from its allies. The initial pledges include German-made Leopard 2 tanks from perhaps a dozen nations, the formidable M1-A1 Abrams from the US and Challenger 2 tanks from Britain.

Now, Kyiv is pushing for fourth-generation fighters. That is triggering a fresh round of debate within Nato. REUTERS