Russian passports are being forced on people in annexed Ukrainian territories and those who refuse are denied essential public services, the Office of the United Nations High Commissioner for Human Rights said on Monday.

Residents who do not take up Russian citizenship were also at greater risk of arbitrary detention, the OHCHR added.

Russian President Vladimir Putin signed a decree in April that allows Ukrainians in occupied areas to potentially be deported if they do not get a Russian passport by 1 July 2024.

UN deputy human rights chief Nada Al-Nashif told the Human Rights Council in a debate on OHCHR's latest report on rights in Ukraine that the policy of mass conferral of passport is deeply concerning as those who refused don't receive social security and healthcare.

Russia had for years been issuing passports to Ukrainians in the eastern Donbas areas held by pro-Moscow separatists as well as in annexed Crimea.

But since Putin launched his full-scale invasion of Ukraine in February 2022, the passport drive has become more aggressive.

An array of routine necessities, such as receiving government benefits, getting or keeping a job and seeking medical treatment require Russian-issued papers, experts and residents have told Agence France-Presse.

Nashif also said "torture remains a brutal reality" for civilians and prisoners of war held by Russia.

Survivors "describe a cruelty that is difficult to imagine," including electric shocks, sexual violence and severe beatings, she said.

"Countless detainees were also forced to praise the Russian Federation, learn and sing Russian songs and suffered severe beatings for failing, or speaking Ukrainian," said Nashif.