KYIV, Ukraine (AP) — Civilians fled intense fighting in eastern Ukraine on Friday as Russian and Ukrainian forces engaged in a grinding battle of attrition for key cities in the country's industrial heartland.

Mostly women, children and elderly residents left on a special evacuation train that departed from the city of Pokrovsk and headed west.

“We live on the front line now,” said Svitlana Kaplun, whose family fled as shelling reached their neighborhood in the city of Krasnohorivka. “The kids are worried all the time, they are afraid to sleep at night, so we decided to take them out.”

After a bungled attempt to overrun Kyiv, Ukraine's capital, in the early days of the war, Russia shifted its focus to an eastern region of coal mines and factories known as the Donbas. The area borders Russia and has been partly controlled by Moscow-backed separatists since 2014.

The fighting there has led to mounting casualties and renewed pleas from Ukraine to the West for more weapons.

Mykhailo Podolyak, an adviser to Ukraine’s president, told the BBC in an interview aired Thursday that the daily loss of 100 to 200 Ukrainian soldiers is the result of a “complete lack of parity” between Ukraine and Russia.

He said only more advanced Western weaponry will turn back the Russian offensive and force Moscow to the negotiating table.

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BIDEN: ZELENSKYY ‘DIDN’T WANT TO HEAR' ABOUT INVASION THREAT

U.S. President Joe Biden said Ukrainian President Volodymyr Zelenskyy “didn’t want to hear it” when American intelligence gathered information in February that indicated Russia was preparing to invade his country.

Speaking to donors Friday at a Democratic fundraiser in Los Angeles, Biden talked about his work to rally support for Ukraine as the war continues into a fourth month.

“Nothing like this has happened since World War II. I know a lot of people thought I was maybe exaggerating. But I knew we had data to sustain” that Russian President Vladimir Putin “was going to go in."

“There was no doubt,” Biden said. “And Zelenskyy didn’t want to hear it.”

Although Zelenskyy has inspired much of the world with his wartime leadership, his preparation for the invasion — or lack thereof — has been controversial.

In the weeks before the war began on Feb. 24, Zelenskyy publicly bristled as Biden administration officials repeatedly warned that a Russian invasion was likely.

At the time, Zelenskyy was concerned that the drumbeat of war was unsettling to Ukraine’s fragile economy.

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MORE STREET FIGHTING IN DONBAS

Fighting in the Donbas has ground on for more than two months, and the slog continued Friday. A provincial governor said Russian and Ukrainian forces battled "for every house and every street” in Sievierodonetsk, a city that recently has been under steady attack.

Sievierodonetsk is in the last pocket of Luhansk province that has not yet been claimed by Russia or Moscow-backed separatists. The Luhansk and Donetsk regions together make up the Donbas.

Luhansk Gov. Serhiy Haidai told The Associated Press that Ukrainian forces retain control of the industrial zone on the edge of the city and some other sections amid the painstaking block-by-block fighting.

An envoy for the Luhansk People’s Republic, a self-proclaimed separatist territory, reported Friday that some Ukrainian troops were trapped inside a chemical plant on the city's outskirts.

“All escape routes have been cut off,” Rodion Miroshnik, Moscow ambassador for the unrecognized republic, wrote on social media.

“They are being told that no conditions will be accepted. Only the laying down of arms and surrender,” he said.

Miroshnik echoed earlier claims by a Russian defense official that civilians remained on the plant's grounds. But he stopped short of reiterating allegations that Ukrainian forces were barring them from leaving.

As of Friday afternoon, there was no response from the Ukrainian side.

Meanwhile, Moscow kept up its artillery strikes on the neighboring city of Lysychansk and surrounding towns and villages, the Ukrainian military said. It also said that Russian troops were preparing to resume an offensive on the city of Slavyansk in the Donetsk region, south of Luhansk.

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ARTILLERY HITS RUSSIAN BASES

An adviser to Ukraine’s president says artillery attacks devastated two Russian bases in the southern Kherson region, which has been under Russian occupation since early in the war.

Oleksiy Arestovych, in his regular online interview, said Friday that the attack on Stara Zburivka, a village along the Dnieper River, killed dozens, including a Russian army general and a general in the FSB intelligence service.

He said the FSB general was tasked with organizing a referendum on whether the Kherson region should join Russia. There was no immediate confirmation of the claim.

Ukraine has claimed to have killed about a dozen generals in the war, but only a few of the deaths have been confirmed.

Arestovych said a separate attack this week on a Russian base in Chkalove killed at least 200 troops, including Arabs, presumably from Syria. He said it was the first confirmed case of Arabs fighting with Russians in Ukraine.

He said in both cases the Ukrainian forces used 155mm howitzers supplied by the West.

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UKRAINE SEEKS MORE WEAPONS

Ukrainian President Volodymyr Zelenskyy said his army’s ability to hold off Russian forces in the Donbas depends on the supply of Western weapons.

Ukrainian troops "are doing everything to stop the offensive, as much as they possibly can, as long as there are enough heavy weapons, modern artillery — all that we have asked for and continue to ask for from our partners,” he said Friday in his nightly video address.

He said Russia wants to destroy every city in the Donbas.

“Every city, that’s not an exaggeration. Like Volnovakha, like Mariupol. All of these ruins of once-happy cities, the black traces of fires, the craters from explosions — this is all that Russia can give to its neighbors, to Europe, to the world.”

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Karmanau reported from Lviv, Ukraine. Associated Press writers Jill Lawless in London and Jamey Keaten in Geneva contributed.

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Follow AP’s coverage of the Ukraine war at https://apnews.com/hub/russia-ukraine

David Keyton And Yuras Karmanau, The Associated Press