ANDRIIVKA, Ukraine — Ukrainian authorities searched for bodies and gathered evidence of Russian atrocities on the ruined outskirts of Kyiv, as the two sides geared up Wednesday for what could be a climactic push by Moscow’s forces to seize Ukraine’s industrial east.

Western governments were set to toughen sanctions against the Kremlin and send more weapons to Ukraine, after President Volodymyr Zelenskyy accused the world of failing to act decisively to end Moscow’s invasion and what he said was a campaign of murder, rape and wanton destruction by Russian forces.

In the scarred and silent streets of towns around Ukraine’s capital that Russian recently troops left, investigators sought to document what appeared to be widespread killings of civilians, some apparently shot at close range, others with their hands bound or their flesh burned. Specialists also cleared mines from the areas.

In Andriivka, a village about 60 kilometers (40 miles) west of Kyiv, two police officers from the nearby town of Makariv came Tuesday to identify a man whose body was in a field beside tank tracks. Capt. Alla Pustova said officers had found 20 bodies in the Makariv area.

Andriivka residents said the Russians arrived in early March and took locals’ phones. Some residents were detained and then released; others met unknown fates. Some described sheltering for weeks in musty, cramped cellars normally used for storing vegetables for winter.

With the sixth week of the war drawing to a close, the soldiers were gone, and Russian armored personnel carriers, a tank and other vehicles sat destroyed on both ends of the road running through the village. Several buildings were reduced to mounds of bricks and corrugated metal. Residents struggled without heat, electricity or cooking gas.

“First we were scared, now we are hysterical,” said Valentyna Klymenko, 64. She said she, her husband and two neighbors weathered the siege by sleeping on stacks of potatoes covered with a mattress and blankets. “We didn’t cry at first. Now we are crying.”

To the north of the village, in the town of Borodyanka, rescue workers combed through the rubble of apartment blocks, looking for bodies. Mine-disposal units worked nearby.

Thwarted in their efforts to take the capital and forced to withdraw, President Vladimir Putin’s forces are now pouring into the Donbas, Ukraine’s eastern industrial eastern heartland, where the Ukraine military has said is it bracing for a new offensive.

Overnight, Russian forces attacked a fuel depot and a factory in Ukraine’s Dnipropetrovsk region, just west of the Donbas, the region’s governor, Valentyn Reznichenko, said on the messaging app Telegram.

In the Luhansk region, which lies in the Donbas, shelling of Rubizhne on Tuesday killed one person and wounded five more, regional governor, Serhiy Haidai, said on Telegram.

Ukrainian forces have been fighting Russia-backed rebels in Luhansk and the other Donbas region, Donetsk, since 2014. Ahead of its Feb. 24 invasion, Moscow recognized the regions as independent states.

Ukrainian officials have stepped up calls for civilians to evacuate from towns in the east near the front line ahead of the anticipated Russian offensive, and some essential services were being moved away. Local authorities in Sloviansk said that postal and pension operations were being moved out and bank branches in town were shutting down.

Ukrainian authorities have said the bodies of at least 410 civilians have been found in towns around Kyiv, and Associated Press journalists in one town, Bucha, counted dozens of corpses in civilian clothes and interviewed Ukrainians who told of witnessing atrocities.

In a video address Tuesday to the U.N. Security Council, Zelenskyy said that civilians had been tortured, shot in the back of the head, thrown down wells, blown up with grenades in their apartments and crushed to death by tanks while in cars.

He said that those responsible should face war crimes charges in front of a tribunal like the one established at Nuremberg after World War II. And he sharply challenged the U.N. to remove Russia from the Security Council and show the world the organization’s worth.

“Where is the peace that the United Nations was created to guarantee?” he asked.

In the wake of the gruesome images out of Bucha and other towns, Western nations have expelled scores of Moscow’s diplomats and were expected to roll out more sanctions Wednesday, including potentially a ban by the European Union on Russian coal imports.

A senior U.S. administration official, speaking on condition of anonymity to discuss the upcoming announcement, said the additional punitive measures would also include a ban on all new investment in Russia.

Russia has insisted its troops have committed no war crimes.

Moscow’s U.N. ambassador, Vassily Nebenzia, said “not a single local person” suffered from violence while Bucha was under Russian control. Using to a tactic Russian officials have often relied on in the face of accusations of atrocities, he said scenes of bodies in the streets were “a crude forgery” staged by the Ukrainians.

On Wednesday, China, which has so far refused to criticize Moscow over the war, called for a probe into the killings, saying that images of civilian deaths are “deeply disturbing” but that no blame should be apportioned until all facts are known.

Elsewhere in Ukraine, the aid group Doctors without Borders said its staff witnessed an attack Monday on a cancer hospital in a residential district of the southern city of Mykolaiv. The group said it was the third known strike in recent days on a hospital in the port city, whose capture is key to giving Russia control of the Black Sea coast.

It said it had no overall death toll, but its team saw one body.

The group said it also saw numerous small holes in the ground, scattered over a large area, that suggested the use of cluster bombs. Russia has denied using cluster munitions in Ukraine. The use of such weapons against civilians can be a violation of international law.

Attacks on medical facilities and workers are deemed war crimes, and Russia has been accused of striking multiple medical facilities during the conflict, including a maternity hospital in the besieged southern port city of Mariupol, scene of some of the worst suffering of the war.

British defense officials said 160,000 people remained trapped by Russian air strikes and heavy fighting in that city, without electricity, communication, medicine, heat or water.

A team from the Red Cross has been trying to get into Mariupol since Friday and got within 20 kilometers (12 miles), but the organization said it was too dangerous to enter.

Negotiators from Russia and Ukraine have been discussing ways to end the fighting. Kremlin spokesman Dmitry Peskov said those talks continue despite the war crime allegations.