Russia's full-scale invasion of Ukraine has triggered "the most massive violations of human rights" in the world today, the head of the United Nations said Monday, as the war pushed into its second year with no end in sight and tens of thousands dead.

The Russian invasion "has unleashed widespread death, destruction and displacement," U.N. Secretary-General António Guterres said in a speech to the U.N.-backed Human Rights Council in Geneva.

Guterres said the Office of the High Commissioner for Human Rights has documented dozens of cases of conflict-related sexual violence against men, women and girls, and serious violations of international humanitarian and human rights law against prisoners of war. Hundreds of cases of enforced disappearances and arbitrary detentions of civilians were also documented, he said.

After failing to capture Kyiv in the opening weeks of the invasion on Feb. 24 last year and suffering a series of humiliating setbacks during the fall, Russia has stabilized the front and is concentrating its efforts on capturing four provinces that Moscow illegally annexed in September — Donetsk, Kherson, Luhansk, and Zaporizhzhia. 

Ukraine, meanwhile, hopes to use battle tanks and other new weapons pledged by the West to launch new counteroffensives and reclaim more of the occupied territory.

Guterres said "attacks on civilians and civilian infrastructure have caused many casualties and terrible suffering."

The intense fighting for territory in eastern Ukraine was in sharp focus Sunday at a Ukrainian field hospital treating wounded from the intense battle for the city of Bakhmut. A constant flow of battered and exhausted soldiers came in on stretchers from the devastated city.

Anatoliy, the chief of the medical service, said his team treats dozens of soldiers every day and barely has time to eat.

"My medics work practically nonstop. Before the full-scale invasion we had 50-60 wounded in a nine-month rotation, and now sometimes we have more (than that) in one day," he told The Associated Press. He gave only one name for security reasons.

During his remarks, the U.N. chief also decried how the Universal Declaration of Human Rights, now 75 years old, has been "too often misused and abused."

"It is exploited for political gain and it is ignored, often, by the very same people," Guterres said. "Some governments chip away at it. Others use a wrecking ball."

"This is a moment to stand on the right side of history," Guterres told the council, the U.N.'s top human rights body. Russia withdrew from its seat last year amid a surge in international pressure over the war in Ukraine.

Guterres' speech came as the Ukrainian military said that Russia launched attacks with exploding drones on several regions of the country from late Sunday until Monday morning, killing two people.

Dozens of high-level envoys at the Geneva meeting — many from Western countries — lashed out at Russia over its conduct of the war. 

At the simultaneous Conference on Disarmament, another U.N.-backed body, delegates criticized Putin's decision to suspend Russia's participation in the New START agreement with the United States, the last nuclear arms control agreement between Moscow and Washington.

Russia was not represented at the council, and its top envoy to the session wasn't expected to speak until Thursday.

Russian officials have shown little sign they may be reconsidering their attack on their neighbor, however.

Kremlin spokesman Dmitry Peskov said Monday: "We aren't seeing any conditions for a peaceful settlement now."

Dmitry Medvedev, the deputy head of Russia's Security Council that is chaired by President Vladimir Putin, went a step further, once again raising the specter of nuclear war and a nightmare outcome to Europe's biggest and deadliest conflict since World War II.

He chided the U.S. and its allies for providing Ukraine with military and other support to help push back the Kremlin's forces. Their longer-term aim, he claimed, is to break up Russia.

Putin has also framed the war in those terms, saying it's an existential risk to Russia.

In the Sunday-Monday attacks, Ukraine's General Staff said Kyiv's forces shot down 11 out of 14 Iranian-made Shahed drones.

Ukraine's presidential office said Monday that at least two civilians were killed and nine others wounded by Russian attacks over the previous 24 hours.

Ukrainian military analyst Oleh Zhdanov said the Russian offensive aimed at securing control of eastern Ukraine has effectively become bogged down while losing "huge numbers of weapons and ammunition."

Zhdanov said the Ukrainian military, in turn, is building up forces for a future counteroffensive in the south while pummeling Russian positions and depots there.

In other developments, the Russian military claimed its forces struck an electronic intelligence center near Brovary, just east of Kyiv.

Russia's Defense Ministry also said that Russian forces struck a special operations center of the Ukrainian armed forces near the western city of Khmelnytskyi.

The ministry didn't say when the strikes were launched, and its claim couldn't be independently verified.

Pamela Falk contributed reporting.

In:
• War
• Ukraine
• Russia
• United Nations