The head of NATO told the BBC that China will face consequences for its support for Russia in the war in Ukraine if it does not change its policy.

Jens Stoltenberg said that Beijing is “trying to have a two-door” on the one hand supporting Russia’s war effort, and on the other trying to maintain its relations with European allies.

“This cannot work in the long term,” Mr Stoltenberg told BBC News during a visit to Washington.

In the wide-ranging interview, Mr Stoltenberg also touched on nuclear weapons and defense spending.

His comments come as Russia shows no signs of easing its war against Ukraine.

At the summit held in Switzerland over the weekend, dozens of nations pledged to back Kiev.

Russia, for its part, called the summit a waste of time and said it would agree to peace talks only if Ukraine surrenders.

When pressed on what NATO members could do about China’s support for Russia, Mr Stoltenberg said there was a discussion about possible sanctions.

He added that China “shares a lot of technology, which is necessary for Russia to build missiles and weapons that it uses against Ukraine.”

He added that “at some stage, we will have to look at some kind of economic cost if China does not change its behavior.”

Beijing already faces sanctions over its support for Russia – last month, the US announced restrictions targeting around 20 companies based in China and Hong Kong.

China has defended its dealings with Moscow, saying it does not sell lethal weapons and “prudently handles the export of dual-use (including civil and military) items in accordance with laws and regulations.”

Stoltenberg’s visit to Washington came as the Kremlin confirmed that Vladimir Putin will travel to North Korea today. Last month Stoltenberg visited China.

“Russia is now increasingly aligning itself with authoritarian leaders,” Stoltenberg told the BBC, referring to Iran, Beijing and North Korea.

Speaking ahead of a meeting with US President Joe Biden, the NATO chief also announced that more than 20 nations are expected to meet the 2% defense spending target this year – more than in any other year since he pledged in 2014.

“That’s good for Europe and good for America, especially because a lot of that extra money is being spent here in the United States,” he said.

Mr Stoltenberg also referred to comments he made to the Telegraph on Sunday which suggested that NATO may be considering increasing the number of nuclear warheads as a deterrent against growing threats from Russia and China.

The comments were slammed as “nothing but another escalation of tension” by Kremlin spokesman Dmitry Peskov.

But Mr Stoltenberg said it was a “general message” that Nato is a nuclear alliance and that any attack on a Nato member “will trigger a response from the entire alliance”.

“NATO’s purpose is not to fight war, its purpose is to prevent war,” he said.