Rescue teams with sniffer dogs combed through debris in a central Ukrainian city on Friday looking for people still missing after a Russian missile strike a day earlier that killed at least 23 people.

Russian forces, meanwhile, pounded other sites in a painstaking push to wrest territory from Ukraine and try to soften unbending morale of its leaders, civilians and troops as the war nears the five-month mark.

The cruise missile strikes on Vinnytsia launched by a Russian submarine on Thursday were the latest incidents to take civilian lives and fan international outrage since President Vladimir Putin launched the invasion on Feb. 24. The campaign now has been focusing on Ukraine's eastern Donbas region, but Russian forces regularly fire upon targets in many parts of the country too.

Ukraine's Interior Ministry claimed Friday that Russian forces had conducted more than 17,000 strikes on civilian targets during the war, driving millions from their homes, killing thousands of fighters and civilians and rippling through the world economy by hiking prices and crimping exports of key Ukrainian and Russian products like foodstuffs, fuel and fertilizer.

More than 73 people — including four children — remained hospitalized and 18 people were missing after Thursday's missile strike, said Oleksandr Kutovyi, spokesman for the emergency service in the Vinnytsia region. Search teams were poring over two sites on Friday — an office building with a medical center inside, and a concert hall near an outdoor recreation area and park, where mothers with children often stroll.

Vinnytsia Gov. Serhiy Borzov said only 10 people among the nearly two dozen killed had been identified so far.

“Russia deliberately hit civilians and all those responsible for the crime must be brought to account,” he said, denouncing the “barbaric behavior by Russia that tramples on international humanitarian law.”

Read:Russian missiles kill at least 23 in Ukraine, wound over 100

Kyrylo Tymoshenko, a deputy head of the president’s office, said three missiles were used.

“There is no answer to the question why yesterday and why in Vinnytsia,” Tymoshenko said. “We expect every second and minute that this could happen in any corner of Ukraine.”

After initial silence after the strikes on Vinnytsia, the Russian military said Friday its forces had struck an officers’ club — which the concert hall has been known for back in Soviet times. Ukrainian authorities insisted the site had nothing to do with the military.

Overall, Ukraine’s presidential office said 26 civilians have been killed and another 190 were wounded by Russian shelling over the past 24 hours. That included three other victims in the Donetsk region, which along with neighboring Luhansk — nearly totally controlled by Russian forces — makes up the broader Donbas region.

“The situation in the Donetsk region is exacerbating every day, and civilians must leave because the Russian army is using scorched earth tactics,” Donetsk Gov. Pavlo Kyrylenko said. It appeared that the cities of Kramatorsk and Sloviansk were next in line for Russian forces, but it wasn't at all clear how soon such a push could begin in earnest.

Elsewhere, authorities in Mykolayiv said there were at least 10 explosions in the southern city overnight, accusing Russian fire of hitting universities. Vitaliy Kim, the head of Mykolaiv’s military administration, posted on social media a video of smoke rising over the strikes.

Separately, the Russian news agency Tass reported Friday, citing Russian-backed separatists, that two civilians were killed and six others were injured after Ukrainian forces allegedly shelled a bus terminal in the Voroshilovsky district of the city of Donetsk.

Also Friday, Daria Morozova, the human rights ombudsperson for the Moscow-backed separatist leadership in Donetsk, said a British “mercenary” died in captivity on Sunday. She said the man, whom she identified as Paul Urey, had died of chronic illnesses and stress.

“From our side, he was given the necessary medical assistance despite the grave crimes he committed,” she said.