Russia-Ukraine updates: Russian missiles hit close to nuclear reactors: IAEA director

At least 18 people are still missing after a deadly missile strike on downtown Vinnytsia in central Ukraine on Thursday, the Ukrainian National Police said.

Three Russian Kalibr missiles launched from a submarine struck an office building and damaged nearby residential buildings in Vinnytsia, located about 155 miles southwest of the Ukrainian capital, Kyiv, on Thursday morning.

At least 23 people -- including 3 children -- died in the attack, Ukraine's State Emergency Service said, and more than a 100 were wounded, some critically.

The bodies of 2 children and 11 adults were yet to be identified on Friday morning, local authorities said.

The strike in the heart of Vinnytsia is “part of a systematic Russian campaign of attacks on residential areas of cities in Ukraine”, the Institute for the Study of War said.

The search continued on Friday morning for at least 18 people who were still missing after the attack. The ongoing rescue operation has been unprecedented in its scale, local officials said, with more than 1,000 rescuers and 200 pieces of equipment being involved in clearing the rubble and searching for those still missing.

Several dozen people were reportedly detained in Vinnytsia on Thursday for questioning under the suspicion of acting as local spotters or aimers on the ground for the Russian strikes.

The eastern city of Mykolaiv also reported 10 powerful explosions on Friday morning. The city's two biggest universities were hit in the attack, wounding at least four people, local authorities said. Russia also struck a hotel and a shopping mall in Mykolaiv on Thursday.

Russian shelling also targeted Kharkiv, another eastern city, on Thursday night. Local officials claimed 2 schools were damaged in the attack.

The European Union and the United Nations strongly condemned Russia for what the EU called a “long series of brutal attacks against civilians."

Russia's missile strikes hit more than 17,000 facilities of civilian infrastructure as opposed to around 300 military facilities since the start of the war, Ukrainian officials said on Thursday.

-ABC News' Edward Szekeres, Yulia Drozd, Fidel Pavlenko and Yuriy Zaliznyak

Russian missiles hit the heart of the central Ukrainian city of Vinnytsia on Thursday morning, killing at least 23 people and wounding dozens, according to Ukraine's State Emergency Service.

Three children were among the dead, the agency said.

The missiles struck an office building and damaged nearby residential buildings in Vinnytsia, located about 155 miles southwest of the Ukrainian capital, Kyiv. The strike also ignited a massive fire that engulfed 50 cars in an adjacent parking lot, according to the National Police of Ukraine. Burned-out vehicles are peppered with holes from the missiles.

The State Emergency Service said about 115 victims in Vinnytsia needed medical attention, with 64 people hospitalized -- including 34 in severe condition and five in critical.

Forty-two people are listed as missing, the agency said.

Many Ukrainians moved to Vinnytsia, a city southwest of Kyiv, to get away from the fighting in eastern Ukraine. Until now, Vinnytsia had been seen as a city of relative safety.

Ukrainian President Volodymyr Zelenskyy called the attack "an open act of terrorism" on civilians.

"Every day Russia is destroying the civilian population, killing Ukrainian children, directing missiles at civilian objects. Where there is no military (targets). What is it if not an open act of terrorism?” Zelenskyy said in a statement via Telegram on Thursday.

War crimes investigators are at the scene studying missile fragments.

Russian missile strikes targeted several other Ukrainian cities on Wednesday and early Thursday, including Kharkiv, Zaporizhia and Mykolaiv.

At least 12 people died in the Zaporizhia strike, which hit two industrial workshops on Wednesday, according to local authorities.

At least five civilians were killed and 30 others injured in Mykolaiv on Wednesday after Russian missiles destroyed a hotel and a shopping mall, the local mayor said. The southern Ukrainian city was shelled again on Thursday morning, but no casualties were immediately reported.

-ABC News' Edward Szekeres, Fidel Pavlenko, Max Uzol, and Yulia Drozd

Michael Carpenter, the U.S. ambassador to the Organization for Security and Cooperation in Europe, is calling the forcible relocation of Ukrainians to Russian filtration camps is "a war crime."

In an interview with ABC News Live on Thursday, Carpenter said the Russians are "trying to take away Ukrainians who might have Ukrainian civic impulses, who are patriots, who want to defend their country." Carpenter said the Russians want to "erase Ukrainian identity" and "the Ukrainian nation state, as the entity that governs people's lives in these regions."

Carpenter said there are at least 18 filtration camps along the Russia-Ukraine border, adding that it’s impossible to get an exact total because many are located in far-flung locations across Russia, including the far east.

-ABC News' Malka Abramoff

The State Department said Wednesday it is aware of unconfirmed reports that another American has been detained by pro-Russian separatists in Ukraine.

According to the Guardian, Murekezi was able to make contact with a family member on July 7 and told them he was being held in the same prison as Alexander Drueke and Andy Tai Ngoc Huynh, two American veterans captured while volunteering for Ukrainian forces. Murekezi has lived in Ukraine since 2020 and was falsely accused of participating in pro-Ukraine protests, according to the report.

"We have been in contact with the Ukrainian and Russian authorities regarding U.S. citizens who may have been captured by Russia's forces or proxies while fighting in Ukraine," a State Department spokesperson said Wednesday. "We call on Russia to live up to its international obligations to treat all individuals captured fighting with Ukraine's armed forces as prisoners of war."

Another American -- Grady Kurpasi -- is also missing in Ukraine. A family spokesperson said the veteran was last seen fighting with Ukrainian forces in late April and is feared to have been either killed or captured.

-ABC News' Shannon Crawford