China has notified several foreign missions in Beijing not to display "politicised propaganda" on their buildings, diplomats told Reuters, adding the request appeared aimed at Ukrainian flags they have displayed since Russia's invasion.

Several foreign missions in China raised the Ukrainian flag, or displayed its image in posters and lights, following the February 2022 invasion that sparked international condemnation of Russia, a close ally of China.

"We and others got a letter calling on embassies and representative offices to refrain from using the outer walls of their buildings for 'politicised propaganda'," one diplomat, whose embassy is displaying a Ukraine flag image, told Reuters on condition of anonymity.

The diplomat said the mission did not intend to comply with the notification.

Three other Beijing-based diplomats confirmed that there had been a notification, adding that while it did not directly mention the Ukraine flag it was clearly aimed at that.

Weeks after Russia launched what it calls its "special military operation" in Ukraine, a poster of a Ukrainian flag on the exterior wall of the Canadian Embassy in Beijing was defaced with anti-NATO graffiti, according to a Reuters witness.

The missions of the European Union, Britain, Germany and Poland in Beijing have also displayed images of Ukrainian flags.

They did not immediately respond to requests for comment.

China has called for a peace in Ukraine but has refrained from condemning its ally Russia, leading to criticism from Western countries.

Some embassies in Beijing are also displaying rainbow flags in support of the LGBT community, to mark the International Day Against Homophobia, Biphobia and Transphobia on Wednesday, and LGBT Pride Month in June.

It was not immediately clear if China, which has faced criticism from rights groups for stifling LGBT activism in recent years, objected to such displays.