Dnipro, Ukraine — Russian missiles hit downtown Lviv early Thursday in what Ukrainian officials called the biggest attack to date on civilian areas in the major western city. Lviv, hundreds of miles from any front line, has been a refuge for Ukrainian civilians fleeing the war raging in the east of their country, and it's considered largely out of harm's way. But nowhere is out of reach for Russia's missiles.

Ukrainian officials said at least four people were killed and nine more wounded when the missiles tore into an apartment building, destroying the roof and top two floors.

Whatever the exact intended target of the Russian missile barrage, Ukraine's air force said the direction was deliberate. It said Ukrainian air defenses had intercepted seven out of a total of 10 cruise missiles fired from the Black Sea toward Lviv around 1 a.m. local time.

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But as Ukraine continues making brutally slow progress in its month-old counteroffensive in the east, the rockets aren't just flying in one direction: Ukrainian forces launched an airstrike deep inside Russian-held territory in the eastern Donetsk region.

Moscow claims the strike hit a residential neighborhood in the Russian-occupied city of Makiivka, but Ukrainian officials say secondary explosions right after the missile struck prove it was a direct hit on a Russian weapons depot.

Right on the front line, meanwhile, there was the renewed specter of a possible nuclear disaster at the sprawling Zaporizhzhia Nuclear Power Plant. Both sides have accused the other of plotting to sabotage the Russian-occupied facility, which is the largest nuclear power plant in Europe.

A team of inspectors from the United Nations' nuclear watchdog agency, the IAEA, have been at the plant for weeks and they've demanded unlimited access to all parts of the compound, to "confirm the absence of mines or explosives at the site."

Regional officials told CBS News on Wednesday that the IAEA experts were being blocked from some parts of the nuclear plant by the Russian forces who control it. 

The IAEA inspectors at the site have said they've yet to see any explosives at the plant, but they've requested full, immediate access to look into Ukrainian President Volodymyr Zelenskyy's claim that Russian troops have rigged explosives on two of the reactor buildings. 

In the nearby city of Zaporizhzhia itself, which Russia has not occupied, government officials have warned residents to prepare for a nuclear emergency.

Olena Zhuk, who chairs the Regional Council, told CBS News it may look "like normal life," with families trying to cling to their routines, but she said the reality was that everyone in the area is living "every second" with the "threat of being murdered."

Zhuk said there was already the constant threat of shelling, given the proximity of deeply entrenched Russian forces across the Dnipro River, but "now, it's even every second [the] threat of explosion [at the] nuclear power plant."

Having fled Russian-held territory with her son once already, mother Yuliya told CBS News she's ready to flee again.

She follows the news closely and said "if evacuation is necessary, we will evacuate. What can we do? We have no other option."

Iryna told us that she and her 8-year-old daughter Alina had gotten used to living under the constant threat of Russian bombardment.

"When we have explosions, we go to a bathroom," she said, adding that her little girl just "falls asleep on the floor."

"She reacts calmly to all of this now," Iryna said. "I think she will be ready for everything."

But as she sat overhearing our conversation, Alina broke down in tears. She didn't look so sure.

In:
• War
• Nuclear Power Plant
• Ukraine
• Russia
• Vladimir Putin