NATO chief Jens Stoltenberg has warned that China is closely watching the lessons of Russia’s “brute force” invasion of Ukraine and could bring war to the Asian region.

Mr Stoltenberg used strong words to accuse China of “bullying its neighbours” and building up its military forces — including nuclear weapons.

He warned that the Info-Pacific region faced “growing challenges” as authoritarian Beijing pushed back against the international rules-based order.

“China is substantially building up its military forces, including nuclear weapons. Bullying its neighbours, and threatening Taiwan. Trying to control critical infrastructure. And spreading disinformation about NATO and the war in Ukraine,” said Mr Stoltenberg during a trip to Japan.

“Beijing and Moscow are leading an authoritarian pushback against the international rules-based order. The Indo-Pacific faces growing challenges, from China’s coercive behaviour to provocations by North Korea.

“And in Europe, Russia continues to wage its brutal war of aggression against Ukraine. This war is not just a European crisis, but a challenge to the world order.”

Mr Stoltenberg said if Russian President Vladimir Putin won in Ukraine it would “send a message” to China that authoritarian regimes can achieve their goals through “brute force”.

“This is dangerous. Beijing is watching closely. And learning lessons that may influence its future decisions,” he warned.

“What is happening in Europe today could happen in East Asia tomorrow. So we must remain united and firm. Standing together for freedom and democracy.”

Mr Stoltenberg was in Japan, which is a member of NATO, and he had earlier visited South Korea.

“The world is at a historical inflection point in the most severe and complex security environment since the end of World War II,” he said with Japan’s premier Fumio Kishida.

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.

Late last year, 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 co-operation with NATO in areas from maritime security and arms control to cyberspace and disinformation will further help to respond to the changing strategic environment, the statement said.