Around 300 volunteer Ukrainian translators, with some also based overseas, are relaying key events from Russia's war on their homeland into Chinese.

Their mouthpieces are a website called "Ukraine News", a Chinese edition of state news agency Ukrinform, and channels on messaging app WeChat and YouTube.

It is for the consumption of a Chinese audience otherwise fed a limited diet of broadly pro-Russian news on the invasion of Ukraine, in a country whose leaders are among Moscow's few remaining friends.

"We channel all our energy, anxiety and grief into doing something," Lidiia Zhgyr, a 29-year-old environmental educator from central Ukraine's Cherkasy, told AFP.

Russia's bloody invasion of Ukraine, now into its fifth week, has killed thousands and forced 10 million from their homes with more than 3.9 mn fleeing the country, according to the UN.

It has provoked widespread global outcry -- although not from Beijing, which has instead provided diplomatic backing for Russia.

During a phone call last week, US President Joe Biden warned his Chinese counterpart Xi Jinping of "consequences" for any material backing of Russia.

But Washington's attempts to isolate Moscow have so far failed to move Beijing's leadership.

And in the gap, Ukrainian volunteers are battling to change Chinese public opinion.

After the initial shock of war, Lidiia decided to help address what she describes as China's "information vacuum" on the conflict.

On a recent weekend in a hipster Beijing cafe, a small group gathered to discuss content for their Chinese-language YouTube channel, which gained over 1,000 subscribers in the week since it was launched -- despite needing a VPN to get over China's Great Firewall.

"The majority of people on Chinese social media support Russia," said Lidiia.

"But I also believe the majority of people don't have access to objective information."

They have set up another channel on messaging app WeChat to post videos of the conflict with Chinese subtitles.

Many videos are blocked by censors even though volunteers avoid posting graphic content, and the apps mostly used by the Ukrainian diaspora are inaccessible in China.

"The huge disadvantage for us is that there are no official news (outlets) from Ukraine in China," she added.

Meanwhile, Russian state media have several reporters based in China.

- Fight for truth -

Many Chinese media outlets have pushed Russian conspiracy theories about US-funded biolabs in Ukraine and blamed NATO for the crisis.

Equally, pro-Russia voices dominate China's highly controlled social media environment.

Valeriia Litovka, a tech worker based in Beijing, says it is "very hard" to share truthful information about the war in Ukraine.

"Still we fight for freedom, for the news, for truth," she told AFP.

"We don't want to offend other countries and Ukrainians respect the rules here... the goal is to give the message that people shouldn't be killed by someone else."

There have been small signs of a shift in Chinese state media coverage, with some recent reports acknowledging civilian casualties caused by Russian invaders.

The volunteers also say Chinese state media have quoted their translations of Ukrainian data on Russian military losses.

"At least one person told me they changed their opinion," said Lidiia.

The Kremlin denies targeting civilians.

- Guilt and resistance -

China's small Ukrainian expat community has dwindled to around a few thousand since the pandemic.

Some say they have received support from Chinese friends as their country has been devastated by war.

"We feel guilty that we are not there," said Valeriia, whose relatives are hiding in bomb shelters in the city of Kharkiv.

Others have had to block acquaintances expressing pro-Putin views on social media.

Ukrainian wine trader Eugene has given up convincing Chinese people online, but helps the cause in other ways.

"I posted several videos on WeChat but later decided to remove them," said Eugene, originally from western Ukraine, giving one name only for privacy reasons.

"I never imagined I would encounter this kind of opposition... it wasted too much energy."

While many pro-Ukraine viral posts and petitions have been censored, a few pockets of support remain -- including the two Weibo accounts operated by the Ukrainian Embassy in China.

Pro-Ukraine Weibo users have translated news about the war into Chinese and debunked Russian propaganda, with some posts gaining hundreds of likes.

An immense volume of materials still needs translating and the volunteers are determined to gradually expand their reach.

"My position is very clear... I speak about the war that Russia is conducting over Ukrainian civilians," said Lidiia.

"This is what I will not stop talking about."