Human Rights Watch is urging Ukraine to stop posting videos of captured Russian prisoners under duress, saying such treatment violated Kyiv's international obligations.

Ukraine has paraded captured Russian soldiers before the media at news conferences in Kyiv, and these images have been spread via official accounts on social media and messaging apps.

Such actions violate the Geneva Conventions that aim to provide a framework for humanitarian law in conflict, the US-based group said in a statement late Wednesday.

"Ukrainian authorities should stop posting on social media and messaging apps videos of captured Russian soldiers that expose them to public curiosity, in particular those that show them being humiliated or intimidated," it said.

"Such treatment of prisoners of war violates protections under the Geneva Conventions intended to ensure dignified treatment of captured combatants on all sides," it added.

It said social media accounts of the Security Service of Ukraine (SBU) had posted videos of captured Russian soldiers "who appear under duress or are revealing their names, identification numbers, and other personal information."

Similar videos has also been posted on accounts apparently run by the interior ministry, it added.

"The Ukrainian authorities should stop posting these videos online," said Aisling Reidy, senior legal advisor at Human Rights Watch.

"The violations by Russian forces are pervasive and widespread, causing intense civilian harm," Reidy said. "At the same time, Ukraine has clear obligations that it must uphold, including lawful treatment of POWs."

The group said it was still awaiting a reply to a letter sent to the Ukrainian authorities expressing concern.

Social media firms should take steps to suppress such content, and media outlets must refrain from broadcasting material of prisoners that breaks humanitarian law, it added.

Human Rights Watch also said it had documented extensive violations and "apparent war crimes" by the Russian side in the conflict including indiscriminate attacks on civilians.