Updated

A massive Russian missile attack across Ukraine on Monday has left at least 31 dead and more than 150 injured, officials say, with one projectile slamming into a children’s hospital in Kyiv. 

Ukraine President Volodymyr Zelenskyy is now vowing to "hold Russia accountable for its acts of terror and Putin for ordering the strikes." 

In a series of messages posted on X, Zelenskyy said more than 40 types of missiles struck the cities of Kyiv, Dnipro, Kryvyi Rih, Slovyansk, and Kramatorsk, damaging apartment buildings and infrastructure as well. 

"Now that the hospital has been damaged by a Russian strike, there are people under the rubble, and the exact number of casualties is still unknown," Zelenskyy said while describing the current situation at the Okhmatdyt Children's Hospital in Kyiv. "Right now, everyone is helping to clear the rubble – doctors and ordinary people." 

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Ukraine children's hospital hit

Rescuers, medical staff and volunteers clean up the rubble and search for victims after a Russian missile hit the country's main children's hospital in Kyiv on Monday, July 8. (AP/Anton Shtuka)

Zelenskyy described the facility as one of the most "important" children’s hospitals in Europe and one that has been "saving and restoring the health of thousands of children." 

"Every time there are attempts to discuss peace with him, Russia responds with attacks on homes and hospitals," Zelenskyy declared. 

"This is why we can only force Russia into peace, and we can only achieve this together with everyone in the world who truly seeks peace," he also said. "This requires sufficient support, determination, truly joint action, and defense – shoulder to shoulder. 

Kyiv missile strike

A woman takes pictures of damage following a missile attack near a train station in Kyiv on Monday, July 8. (AP/Anton Shtuka)

Strikes in Kryvyi Rih, Zelenskyy's birthplace in central Ukraine, killed 10 people and injured 47 in what the head of city administration, Oleksandr Vilkul, said was a massive missile attack, according to The Associated Press. Seven people were killed in Kyiv, authorities said.

In Kyiv, Mayor Vitali Klitschko said at least 16 people, seven of them children, were injured at the children's hospital.

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Ukraine children's hospital evacuation

Women are seen holding children outside the Okhmatdyt Children's Hospital in Kyiv following the attack on Monday. (Oleksandr Gusev/Global Images Ukraine via Getty Images)

On the hospital’s main 10-story building, windows and doors were blown out and walls were blackened, the AP reports. Blood spattered the floor in one room. The intensive care unit, operating theaters and oncology departments all were damaged, officials said.

The attack also forced the evacuation of the hospital and its temporary closure. Some mothers carried their children away on their backs, while others waited in the courtyard with their children as calls to doctors’ phones rang unanswered.

Marina Ploskonos said her 4-year-old son had spinal surgery Friday.

"My child is terrified," she told the AP. "This shouldn’t be happening, it’s a children’s hospital," she said, bursting into tears.

Aftermath of missile strike in Ukraine

People and medical staff are seen responding to the missile strike against a children's hospital in Kyiv. (AP/Anton Shtuka)

Ukraine’s Security Service said it found wreckage from a Russian Kh-101 cruise missile at the site and had opened proceedings on war crime charges. The Kh-101 is an air-launched missile that flies low to avoid detection by radar. Ukraine said it shot down 11 of 13 Kh-101 missiles launched Monday.

Meanwhile, Russia’s Defense Ministry said the strikes targeted Ukrainian defense plants and military air bases and were successful. It denied aiming at any civilian facilities and claimed without evidence that pictures from Kyiv indicated the damage was caused by a Ukrainian air defense missile.

Ukraine Childrens Hospital

Rescuers and volunteers clean up the rubble and search for victims after a Russian missile hit the Okhmatdyt Children's Hospital in Kyiv, Ukraine, on Monday, July 8. (AP Photo/Efrem Lukatsky)

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The attacks unfolded a day before the U.S. is scheduled to convene a NATO summit in Washington, D.C.

The Associated Press contributed to this report.