'Massive' barrage of Russian missiles target Ukraine, killing 21 and striking children's hospital
More than 40 missiles were fired, President Volodymyr Zelenskyy said.
LONDON and KYIV -- At least 21 people were killed across Ukraine early on Monday, as Russia launched a barrage of more than 40 missiles in a "massive" attack, Ukrainian officials said.
Okhmatdyt Children's Hospital in Kyiv was damaged, along with residential areas and other infrastructure, President Volodymyr Zelenskyy said on social media.
It was not immediately clear whether there were casualties at the hospital, but children were believed to be stuck beneath the rubble, Zelenskyy said. Doctors, hospital staff and first responders were digging through the debris, he said. The hospital is among the most well respected children's hospitals in Ukraine.
"And the entire world must use all its determination to finally put an end to the Russian strikes. Killing is what Putin brings," Zelenskyy said. "Only together can we bring real peace and security."
The attack, which is among the largest Russian strikes in months, comes a day before U.S. President Joe Biden begins a 3-day NATO summit in Washington, where the group is expected to discuss support for Ukraine.
The alliance is expected to make "significant" announcements about increased military and financial support for Ukraine, a senior White House official said last week.
Photos and videos shared Monday by Zelenskyy and those at the hospital appeared to show bloodied doctors carrying out children, a building in the hospital grounds reduced to rubble and the exterior of the main building blown out. One image appears to show young patients sitting on the street with their IVs after the explosion.
A doctor at the hospital told local media the missile destroyed a building where two operations were happening at the time.
The Security Service of Ukraine said in a statement it had opened a criminal investigation into the strike on the hospital, which it called a "war crime." The service said a Russian Kh-101 missile struck the building, according to its preliminary findings.
The missiles targeted cities including Kyiv, Dnipro, Kryvyi Rih, Slovyansk and Kramatorsk, Zelesnkyy said. At least eight of the dead were in Kyiv, officials said.
At least 10 people were killed and several others injured Monday morning in Russian airstrikes on Kryvyi Rih, a city in central Ukraine and Zelenskyy's hometown, officials said. Another three people were killed in Russian airstrikes on the eastern Ukrainian city of Pokrovsk, officials said.
ABC News' Joe Simonetti and Morgan Winsor contributed to this report.