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

Russian shelling killed at least 13 civilians in eastern Ukraine's Dnipropetrovsk region early Wednesday morning, local authorities said.

At least 11 others were injured, with five people remaining in critical condition, according to Dnipropetrovsk Oblast Gov. Valentyn Reznichenko, who said Russian forces fired 80 rockets at residential areas in the region.

"They deliberately and sneakily struck when people were sleeping in their homes," Reznichenko said in a statement Wednesday.

Russian shells hit civilian objects in the region's southern Nikopol district from the area of the Zaporizhzhia nuclear power plant, which is occupied by Russian troops some 30 miles away, according to Ukrainian President Volodymyr Zelensky's chief of staff, Andriy Yermak.

More than 20 high-rise buildings, two schools, a city council building and several other administrative buildings in the city of Marhanets were damaged in the attack, Yermak said.

The city of Nikopol and the surrounding areas have been subject to regular shelling for several weeks. Russian forces fired 120 MLRS missiles at Nikopol early Tuesday, damaging several residential and commercial buildings.

Russian missiles also struck the southern city of Mykolaiv on Wednesday, injuring three people, including a child.

Meanwhile, explosions and casualties were also reported in the eastern Sumy region on Wednesday morning.

-ABC News' Edward Szekeres, Yuriy Zaliznyak and Max Uzol

Russian forces shelled the outskirts of Zaporizhzhia overnight, killing at least one civilian, the city's acting mayor, Anatoly Kurtev, said Wednesday.

The strike on the Kushugum community left three homes destroyed and almost 30 others damaged. The civilian who died was a woman, according to Kurtev.

That same night, Ukrainian troops defending the Zaporizhzhia region shot down two Russian missiles, Kurtev said, citing "preliminary information."

"Take care of yourself and your loved ones," the acting mayor said in a statement on Telegram. "Don't ignore the air alarm!"

A source familiar with the operation confirmed to ABC News that Ukraine was behind a Tuesday explosion in Russia-annexed Crimea. One person died from the blasts in Novofedorivka in Crimea, Russia's semi-official Interfax reported, citing Crimean official Sergei Aksyonov.

This is the first major attack in Crimea since the war began in February.

-ABC News’ Britt Clennett and Dada Jovanovic

The U.S. estimates that 70,000 to 80,000 Russians have been killed or wounded since the start of the war in Ukraine, Colin Kahl, the undersecretary for defense for policy at the Department of Defense, told reporters Monday.

"There's a lot of fog in war, but, you know, I think it's safe to suggest that the Russians have probably taken 70 or 80,000 casualties in less than six months," Kahl said. "I think that's kind of in the ballpark."

Kahl would not talk about specific Ukrainian casualties but noted that "Ukrainian morale and will to fight is unquestioned and much higher, I think, than the average morale and will to fight on the Russian side." He added, "I think that gives the Ukrainians a significant advantage."

Russia has gone through "a significant percentage of their precision guided munitions and their standoff munitions," Khal said. Because they’re "running low," they’re not using them as much and keeping what they have in reserve for other contingencies, he said. And because of sanctions against Russia, it will be tougher for the military to rebuild their stocks, he said.

-ABC News’ Luis Martinez