5 professors from top Chinese universities wrote an open letter condemning Russia's invasion of Ukraine, marking a departure from China's pro-Russian online sentiment

• Top Chinese historians and university alumni have spoken up against Russia's invasion of Ukraine.
• Their anti-war messages contradict the Chinese government's ban on criticisms of Russia.

"In the midst of all the noise, we felt the need to make our voices heard."

That's what a group of five Chinese historians wrote in an open letter condemning the invasion of Ukraine. They number among the growing anti-war voices in China breaking ranks with their government's ban on criticisms of Russia.

The letter was signed by five history professors from top Chinese universities: Nanjing University's Sun Jiang, Peking University's Wang Lixin, Hong Kong University's Xu Guoqi, Tsinghua University's Zhong Weimin, and Fudan University's Chen Yan.

"As a country that was once also ravaged by war ... we sympathize with the suffering of the Ukrainian people," their letter read, per US-funded nonprofit outlet Radio Free Asia (RFA). Calling for an immediate end to the fighting, the letter warned the invasion could spark a "massive, global war."

The historians did not immediately respond to Insider's request for comment.

The letter was censored hours after it was posted on social media platform WeChat on Saturday, according to BBC Chinese, although copies of it can still be found online.

Separately on Monday, more than 130 university alumni from China's top institutions signed a petition to condemn the invasion, calling on Beijing to honour commitments it made under UN Resolution 984. In the joint security pact signed in 1994, China committed to providing security assurance to countries without nuclear weapons, in the event that they are the subject of foreign aggression.

It is unclear where the petition was originally posted, but it has been widely shared online.

Lu Nan, a Renmin University journalism graduate, was one of those who signed the petition. "We all have a common purpose, which is to oppose war and maintain peace," Lu told RFA. "Russia's invasion of Ukraine is a fundamental challenge to human conscience."

"Ukraine didn't invade Russia. It's a sovereign country and its people are peace-loving," he added.

Such anti-war messages contradict the Chinese government's messaging. China has avoided calling Russia's attack on Ukraine an invasion.

On Chinese social media, online opinion has also been mostly pro-Russian, pro-war, and pro-Putin, the New York Times reported.

Last week, Horizon News, which is owned by the Chinese Communist Party, accidentally published editorial instructions to cover Russia in a good light. The post on Twitter-like Weibo was later deleted, The Washington Post reported.

A top Chinese state-media editor later said Beijing needs to back Russia over Ukraine because it needs Moscow's support to assert dominance over Taiwan.