GENEVA, Switzerland - UN rights chief Volker Turk on Friday slammed the human cost of Russia's "senseless" year-old war in Ukraine and urged greater efforts to ensure justice for victims.

Turk said the civilian toll was "unbearable", with his office verifying that at least 8,006 civilians had been killed and 13,287 injured up to February 15, though the real figures are much higher.

The United Nations' High Commissioner for Human Rights said attempts to establish accountability and justice for international law violations had to intensify.

"As we mark one year since Russia's war against Ukraine began, I deplore the terrible human cost of this senseless conflict," Turk said in a video statement.

"The toll on civilians is unbearable. Nearly 18 million people are in dire need of humanitarian assistance. Some 14 million people have been displaced from their homes."

He said most of those who remained in conflict-affected areas were older people who were reluctant or not able to leave, adding that  children have seen their education halted by attacks on schools.

"Efforts to establish accountability and justice for violations of international law must intensify and deepen," Turk said.

"It is equally vital that victims can access reparations and the practical assistance they desperately need, without first having to wait for the outcomes of formal legal proceedings."

Turk said the war had resulted in higher food and fuel costs that had "deepened misery on a global scale".

"It must end now."

According to the UN Human Rights Office's monitoring mission in Ukraine, of the adult civilian casualties whose sex was known, men accounted for 61.1 percent of civilian casualties and women for 39.9 percent.

At least 487 children have been killed and 954 injured.

Some 90.3 percent of civilian casualties were caused by explosive weapons with wide area effects, including artillery shells, cruise and ballistic missiles, and air strikes. Most occurred in populated areas.

The office has also recorded 219 civilians killed and 413 injured by mines and explosive remnants of war.

Furthermore, the office said it has information regarding 30 civilians killed and 130 injured within Russia, but did not have corroborating information.