Pavlohrad, Ukraine — The U.S. government said Monday that Russia had lost some 20,000 troops amid the fierce battle for the eastern Ukrainian city of Bakhmut, which Russia has claimed repeatedly to be on the verge of seizing, since December alone. National Security Council spokesman John Kirby said Monday that Russia's casualty count rose to 100,000 when including wounded Russian fighters. 

"Ukraine's defenses in the areas surrounding Bakhmut remain strong," Kirby told reporters on virtual briefing Monday. "For Russia, this attempted offensive has come at a terribly high cost. Russia has exhausted its military stockpiles and its armed forces. Since December alone… we estimate that Russia has suffered more than 100,000 casualties, including over 20,000 killed in action, nearly half of whom were Wagner soldiers, the majority of whom were Russian convicts thrown into combat in Bakhmut, without sufficient combat or training, combat leadership, or any sense of organizational command and control."

EDITOR'S NOTE: A U.S. official clarified Kirby's remarks to CBS News on Tuesday, saying the 100,000 total casualties referred to those sustained by Russia across Ukraine since December, and the 20,000 deaths referred to on Monday were part of that total. This article has also been corrected to reflect Kirby's current role as spokesman for the NSC, not the Defense Department as previously stated.

Russia dismissed the casualty toll from Washington on Tuesday as having been "plucked from thin air," but it did not provide any of its own statistics. The last time Moscow gave any indication about its troop loses in Ukraine was September, when the defense minister said about 6,000 service members had been killed.   

Kirby said he didn't have casualty figures for Ukraine's forces in Bakhmut, but the battle has been grueling for both sides. Most of those killed in the war since Christmas have died in the fight, and Russia has been accused of throwing wave after wave of poorly trained, poorly equipped fighters at the front line. 

It emerged this week, however, that a former U.S. Marine is among those to have fallen on the Ukrainian side of the front line. 

Former Marine Cooper "Harris" Andrews, 26, from Cleveland, was killed in Ukraine last week, his mother told CNN. She said he was hit by a mortar while helping evacuate civilians from Bakhmut, where Russian and Ukrainian forces have fought each other to a bloody stalemate.

As anticipation mounts for a looming Ukrainian spring counteroffensive, Russia has been taking preemptive revenge on the Ukrainian people, targeting civilian areas far from the front lines.

For three days Russia has fired salvos of missiles and explosive drones at cities across Ukraine, including a second barrage that targeted the capital Kyiv. Ukraine's air defense systems stop many of the Russian missiles — a wall of protection that President Volodymyr Zelenskyy promised his country he was working to bolster with the help of the U.S. and other "partners."

Zelenskyy said Monday night that during just seven hours, between midnight and Monday morning, Ukraine had "managed to shoot down 15 Russian missiles. But unfortunately, not all of them."

Several missiles slipped through the air defense net, and at least one of them slammed into the eastern town of Pavlohrad, about 70 miles from the front line and Russian-occupied ground.

A huge fireball lit up the skies amid the strikes. Ukrainian authorities would only say "an industrial complex" was struck. But not all the missiles hit their mark.

Two people were killed and 40 more injured in the attack on Pavlohrad. Residents told CBS News that air raid sirens blared all night.

As the alarm was raised, Olga and Serheii Litvenenko took shelter in a garage on their property. They went back inside at about 2:30 a.m., but as the sound of explosions echoed closer, they decided it was time to seek shelter again.

"I told to my wife, 'Let's run, it could hit the house,'" Serheii said, so they quickly pulled on their shoes and headed back toward the garage.

Then there was an explosion. Serheii said a rocket slammed right into the garage as they approached it. He pointed to the charred remains of their car.

"It overturned in front of my eyes… There was so much smoke, dust, and the fire started," he recalled. He said he ran to a well and tried to connect a hose to douse the flames, but the pump was damaged, and he had to resort to a bucket.

"I was pouring [water] on the car, I wanted to save it. But I couldn't… It just burned in a minute," he said.

Serheii, who spent 36 years working in the mines around Bakhmut, knows how close a call he and his wife had, and the shock was still fresh.

"I got lucky," Serheii told CBS News. "Extremely lucky. I'm still trying to process exactly what happened. In my mind, it feels like I'm somewhere else."

"I have a son on the front line right now," Serheii said, cursing Russian President Vladimir Putin as a "beast."

Ukrainian soldiers and civilians alike are all bracing for more pre-emptive Russian strikes ahead of the much-anticipated spring counteroffensive.

A senior Ukrainian defense official told CBS News that preparations were nearly complete, but that recent rainy weather may have delayed the start. When it does begin, he said, "the whole world will know."

In:
• U.S. Marine Corps
• War
• Bakhmut
• Ukraine
• Russia
• War Crimes
• Vladimir Putin