KYIV - Weapons experts from France are helping their Ukrainian counterparts collect evidence of possible Russian war crimes in the northern region of Chernihiv, Ukraine's prosecutor general said on Friday.

The French Gendarmerie's experts, including specialists in drone modelling, ballistics and weapons of mass destruction, have been collecting evidence at sites of destruction from Russian shelling.

They replaced group of gendarmerie forensic experts who arrived in mid-April to help establish what happened in Bucha, near Kyiv, where the killing of many civilians provoked a global outcry.

"It will soon be two months since (French experts) have been with us 'on the ground'," Prosecutor General Iryna Venediktova wrote on her Facebook account.

"They work in the Chernihiv region and conduct research at sites destroyed by shelling," she wrote. "These war crimes must be punished, and we are ready to do together everything to do so."

The Chernihiv region has been shelled frequently since Russia invaded on Feb. 24. Ukraine is also investigating potential war crimes by Russian soldiers in Chernihiv during their occupation in March.

Russia denies targeting civilians and has rejected allegations of war crimes in what it calls a "special military operation" to demilitarise and "denazify" Ukraine. Kyiv and its allies say Russia invaded its neighbour without provocation.

(Reporting by Natalia Zinets in Kyiv; Writing by Lidia Kelly in Melbourne; Editing by William Mallard)