KYIV, Ukraine — Ukraine told residents of its industrial heartland to leave while they still can and urged Western nations to send “weapons, weapons and weapons” Thursday after Russian forces withdrew from the shattered outskirts of Kyiv to regroup for an offensive in the country’s east.

Russia’s six-week-old invasion failed to take Ukraine’s capital quickly and achieve what Western countries say was President Vladimir Putin’s initial aim of ousting the Ukrainian government. Russia’s focus is now on the Donbas, a mostly Russian-speaking region in eastern Ukraine.

In Brussels, Ukrainian Foreign Minister Dmytro Kuleba urged NATO to provide more weapons and help his war-torn country prevent further alleged atrocities. Ukrainian authorities are working to identify hundreds of bodies found in Kyiv’s northern outskirts after Russian troops withdrew and to document evidence of possible war crimes.

“The more weapons we get and the sooner they arrive in Ukraine, the more human lives will be saved,” Kuleba said as he arrived at NATO headquarters for talks with the military organization’s foreign ministers.

While NATO is striving to avoid actions that might draw any of its 30 members into a war with Russia, Secretary-General Jens Stoltenberg urged nations that belong to the Western alliance to send Ukraine more weapons, and not just defensive arms.

West Reluctant to Send Planes, Tanks

Western countries have provided Ukraine with portable anti-tank and anti-aircraft weapons, but they have been reluctant to supply aircraft, tanks, or any equipment that Ukrainian troops would have to be trained to use.

Moscow announced more than a week ago that it planned to concentrate its forces in the east, and they have largely withdrawn from Kyiv and the north. Growing numbers of Putin’s troops, along with mercenaries, have been reported moving into the Donbas, where Russia-backed separatists have fought Ukrainian forces for eight years and control some territory.

Ukrainian Deputy Prime Minister Iryna Vereshchuk urged civilians to evacuate to safer regions before it was too late. She said Ukrainian and Russian officials agreed to establish 10 civilian evacuation routes Thursday.

The change of Russia’s focus brought relief to Chernihiv, a city near Ukraine’s northern border with Belarus that was encircled and cut off for weeks,

The departed troops left behind twisted buildings and traumatized residents, who clambered over rubble and passed cars destroyed by the fighting. Dozens of people lined up for food, diapers and medicine Thursday at a shattered school now serving as an aid-distribution point.

The blackboard in one classroom was chalked, “Wednesday the 23rd of February — class work.” Russia invaded Ukraine the next day, besieging Chernihiv as its troops tried to sweep south towards the capital.

“At last we can bring food,” said Viktiriia Veruha, who was distributing aid at the school. “We can now bring food, medicine, and we can evacuate people from Chernihiv, which is also very important.”

Residents Spent 40 Days in Basement

Tatiana Nesterenko, who left the city and crossed to Medyka in Poland, joined more than 4.3 million refugees who have fled Ukraine since the war started.

“We spent 40 days in a basement,” she said. ”Our home was destroyed by an airstrike. … Many people are homeless now, and there were a lot of victims. There was no help, no volunteers for us. We extinguished the fire by ourselves.”

Britain’s defense ministry said Thursday that Russia was targeting the “line of control” between Ukrainian-held and rebel-controlled areas in the Donbas with artillery and airstrikes and hitting infrastructure targets around Ukraine to wear down the Ukrainian defense.

Russia’s Defense Ministry said it struck fuel storage sites around the cities of Mykolaiv, Zaporozhe, Kharkiv, and Chuguev overnight using cruise missiles fired from ships in the Black Sea.

A Ukrainian naval vessel caught fire under unclear circumstances in the besieged port city of Mariupol, satellite photos analyzed Thursday by The Associated Press show. The images from Planet Labs PBC appear to show the Ukrainian command ship Donbas burning at the Sea of Azov port on Wednesday afternoon as a nearby building also burned.

Mariupol has experienced some of the war’s greatest deprivations. Russian forces are fighting street by street to capture the city; doing so would allow Russia to secure a land corridor to the Crimean Peninsula, which Moscow seized from Ukraine in 2014.

5,000 Civilians Killed in Mariupol

Mariupol Mayor Vadym Boichenko said more than 5,000 civilians have been killed, including 210 children. British defense officials estimate that 160,000 people remain trapped in the city, which had a prewar population of 430,000.

Ukrainian authorities said the bodies of least 410 civilians were found in Bucha and other towns around Kyiv, victims of what Ukrainian President Volodymyr Zelenskyy has portrayed as a Russian campaign of murder, rape, dismemberment and torture.

In areas north of the capital, Ukrainian officials gathered evidence of Russian atrocities amid signs Moscow’s troops killed people indiscriminately before retreating. Some victims were apparently shot at close range or died with their hands bound.

Western officials warned that similar atrocities were likely to have taken place in other areas occupied by Russian troops. Zelenskyy accused Russian forces of removing dead bodies in an attempt to cover up war crimes in areas still under their control, “afraid that the global anger over what was seen in Bucha would be repeated.”

“This is only an attempt to hide the evidence and nothing more,” he said in a nighttime video address.

International Court Begins War Crimes Probe

The International Criminal Court opened an investigation into possible war crimes in Ukraine before the grim discoveries near Kyiv fueled more urgent calls for the perpetrators of civilian atrocities to be brought to justice. Ukrainian authorities were transferring piles of body bags to a facility for identification and investigation,

The Kremlin insists its troops have committed no war crimes and alleged the Ukrainians staged images of brutality coming out of Bucha and nearby towns.

The French government summoned Russia’s ambassador over a tweet suggesting that images of dead civilians were phony. The tweet on Thursday, which has since been removed but reprinted by numerous French media outlets, showed a street in Bucha with a demolished tank and numerous journalists under the caption “film set.”

French Foreign Minister Jean-Yves Le Drian called the tweet “indecent.”

Two former German government ministers submitted a criminal complaint with federal prosecutors, hoping to use national laws to seek a war crimes probe against Russian officials, including Putin and Russian military personnel.

Lawyer Nikolaos Gazeas, who compiled the 140-page criminal complaint, cited a report Thursday by news weekly Der Spiegel that said Germany’s foreign intelligence agency had intercepted radio messages between Russian soldiers discussing the killings of civilians in Bucha.

US Sanctions Putin’s Adult Daughters

Members of the U.S. House late Wednesday overwhelmingly passed legislation calling for a federal government report on evidence of war crimes committed during the Russian invasion of Ukraine.

In reaction to the alleged atrocities, the U.S. announced sanctions against Putin’s two adult daughters and said it is toughening penalties against Russian banks. Britain banned investment in Russia and pledged to end its dependence on Russian coal and oil by the end of the year.

The European Union is also expected to take additional punitive measures, including an embargo on Russian coal.