An open letter written by five historians denounced the war and called on Beijing to make its stance clearer

• Ukraine invasion: latest updates

For Xu Guoqi, a Chinese historian, Beijing’s reluctance to denounce Vladimir Putin’s invasion of Ukraine is alarming. “I’m a historian of the first world war. Europe sleep-walked into a huge conflict over 100 years ago, which also had had enormous consequences for China,” Xu said. “The world may be at the point of no return again”.

But looking at how Chinese diplomats are responding to it, and how Chinese people have talked about it on social media in the past week, he said, “I’m afraid it seems we still have not learned the lessons of the past tragedies. As a historian I’m very disappointed.”

Beijing is walking a diplomatic tightrope but crisis also offers the opportunity to express grievances against its adversaries

• Russia-Ukraine crisis: live news

The news came as a surprise to many in Beijing. Barely 24 hours ago, Chinese pundits predicted that a war in Ukraine was not inevitable. In New York, as Russia geared up for a full-on assault on its neighbour, China’s UN envoy, Zhang Jun, urged in a security council meeting that “the door to a peaceful solution to the Ukraine issue is not fully shut, nor should it be shut”.

But when people in Kyiv woke up to sound of bombs in what the Nato chief called a “deliberate, cold-blooded” invasion, the door had clearly been closed. China’s state media, however, insisted it was a “special military action” by Russia. Quoting Vladimir Putin, China’s central television tweeted: “Russia was left with no other choice.”