Ukrainian authorities on June 28 arrested a person they accused of helping Russia direct a missile strike that killed at least 11 people and injured 61 at a restaurant in Kramatorsk the night before.
Ukraine's Security Service (SBU), working with special police forces, detained the person, Ukrainian President Volodymyr Zelenskiy said on Telegram on June 28.
SEE ALSO: Ukraine Live Briefing: 3 Children Among Dead In Sumy, Odesa"Whoever helps Russian terrorists to destroy lives deserves the maximum penalty," Zelensky said in his nightly address.
He did not identify the person who was detained in the attack, but the SBU said earlier it was a man who worked for a gas transportation company and is suspected of filming the restaurant for the Russians and informing them about its popularity.
Twin sisters who were to have turned 15 in September were among the 11 people killed, regional officials said earlier on June 28.
Kramatorsk Mayor Oleksandr Honcharenko said on Facebook that a third minor, a boy, had been killed and his body pulled from the rubble.
Kramatorsk was targeted by two Russian missiles on June 28 in the evening, with one hitting a crowded restaurant and shopping center in the city center and a second hitting a village on the outskirts of the city in Ukraine's eastern Donetsk region.
The head of the Donetsk military administration, Pavlo Kyrylenko, said 18 multistory buildings, five schools, and two kindergartens, had been destroyed, in addition to the shopping center and pizza restaurant, which was reportedly frequented by journalists, aid workers, and soldiers.
Separately, a strike in Ukraine's eastern Kharkiv region killed three civilians near their homes, Kharkiv regional Governor Oleh Synehubov said on Telegram.
Kramatorsk is a major city in the Donetsk region that houses the Ukrainian Army's regional headquarters and is likely a key objective in any Russian advance to the west. It has been a frequent target of Russian attacks.
It was hit on May 2 by rockets fired from a Tornado multiple-rocket launcher. Russian forces claimed a railcar full of ammunition was destroyed in that strike.
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In April last year, 63 people were killed in a Russian strike on Kramatorsk's main railway station. At least two other strikes have hit apartment buildings and civilian infrastructure in the city this year.
In response to the outcry over the attack, Kremlin spokesman Dmitry Peskov said on June 28 claimed Russia only carries out strikes "that are in one way or another linked to military structure."
Moscow has repeatedly denied shelling the civilian population in Ukraine despite evidence and testimony to the contrary.
Valeriy Zaluzhniy, commander in chief of Ukrainian forces, said he spoke by phone with U.S. Army General Mark Milley, chairman of the Joint Chiefs of Staff, about the situation at the front line was discussed.
Ukrainian forces "continue to conduct offensive actions" and "are advancing," he said. "The enemy is putting up a strong resistance, at the same time suffering heavy losses."
Russian forces are trying to hold on to positions by continuously mining the area, Zaluzhniy said on social media. He said he told Milley the Ukrainian military urgently needs weapons, ammunition, and demining equipment.