KYIV, Ukraine (AP) — Ukraine told residents of its industrial heartland to leave while they still can and urged Western nations to send “weapons, weapons, 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 like those reported in Kyiv’s northern outskirts. Ukrainian authorities are working to identify hundreds of bodies found in Bucha and other towns after Russian troops withdrew and to document evidence of possible war crimes.

“My agenda is very simple. … it’s weapons, weapons and weapons,” Kuleba said as he arrived at NATO headquarters for talks with the military organization’s foreign ministers.

“The more weapons we get and the sooner they arrive in Ukraine, the more human lives will be saved,” he said.

The Western alliance is striving to avoid actions that might pull any of its 30 members directly into the war. Still, NATO Secretary-General Jens Stoltenberg urged member nations to send Ukraine more weapons, and not just defensive arms.

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.

Asked what more his country was seeking, Kuleba listed planes, land-based missiles, armored vehicles and air defense systems.

Moscow announced more than a week ago that it planned to concentrate its forces in the east, and they have largely withdrawn from Kyiv and the north.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 two areas.

Ahead of its Feb. 24 invasion, Moscow recognized the Luhansk and Donetsk areas as independent states. Military analysts have said Putin could be seeking to expand into government-controlled territory.

Ukrainian Deputy Prime Minister Iryna Vereshchuk urged civilians to evacuate to safer regions before it was too late.

“Later, people will come under fire, and we won’t be able to do anything to help them,” Vereshchuk said.

She said Ukraine and Russian officials agreed to establish 10 civilian evacuation routes from Donetsk, Luhansk and the Zaporizhzhia region. She said residents would be able to seek safety in the cities of Zaporizhzhia in southeast Ukraine and Bakhmut in the east.

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.”

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

A cause for the fire remained unclear.

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 continuous land corridor to the Crimean Peninsula, which Moscow seized from Ukraine in 2014.

Mariupol Mayor Vadym Boichenko said more than 5,000 civilians have been killed during weeks of Russian bombardment and street fighting, including 210 children. British defense officials said 160,000 people remained trapped in the city, which had a prewar population of 430,000.

Oleksandr Shputun, spokesman for the General Staff of the Ukrainian Armed Forces, reported Thursday that Ukraine’s second-largest city, Kharkiv, remained blockaded near the Donbas. He said Russian forces also were carrying out “brutal measures” in the southern Kherson region, which they hold.

The International Criminal Court has opened an investigation into possible war crimes in Ukraine. In areas north of the capital, Ukrainian officials gathered evidence of Russian atrocities amid signs Moscow’s troops killed people indiscriminately before retreating.

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

“We have information that the Russian troops have changed tactics and are trying to remove the dead people, the dead Ukrainians, from the streets and cellars of territory they occupied,” he said in a nighttime video address. “This is only an attempt to hide the evidence and nothing more.”

The Kremlin insists its troops have committed no war crimes and alleged the Ukrainians staged the images of brutality coming out of Bucha, where piles of body bags were getting taken to a facility for identification and investigation.

Two former German government ministers have submitted a criminal complaint with federal prosecutors seeking the opening of a war crimes probe against Russian officials, including President Vladimir Putin and Russian military personnel.

The pair want to use national laws allowing for the prosecution in Germany of individuals accused of serious crimes committed elsewhere.

Lawyer Nikolaos Gazeas, who compiled the 140-page criminal complaint on their behalf, 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.

Gazeas said parallel probes in multiple jurisdictions made sense and could be mutually reinforcing. 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.

Zelenskyy said the sanctions would not be effective unless they included a ban on Russian oil imports, on which Europe relies heavily. He said the West’s sanctions on Russia so far “can’t be called commensurate to the evil the world saw in Bucha” and elsewhere.