ZAPORIZHZHIA, Ukraine >> The couple cowered under a blanket before dawn Sunday when they heard missiles headed again for their city, which has suffered repeated barrages as Russian and Ukrainian forces battle for control of territory that Moscow has illegally annexed.

“There was one explosion, then another one,” Mucola Markovich said. Then, in a flash, the fourth-floor apartment he shared with his wife was gone, the 76-year-old said, holding back tears.

The overnight Russian missile strikes on the city of Zaporizhzhia brought down part of a large apartment building, leaving at least a dozen people dead.

“When it will be rebuilt, I don’t know,” Markovich said. “I am left without an apartment at the end of my life.”

The strikes come as Russia has suffered a series of setbacks nearly eight months after invading Ukraine in a campaign many thought would be short-lived. In recent weeks, Ukrainian forces have staged a counteroffensive, retaking areas in the south and east, while Moscow’s decision to call up more troops has led to protests and an exodus of tens of thousands of Russians.

The latest setback for Moscow was an explosion Saturday that hit a huge bridge linking Russia with the Crimean Peninsula, which Moscow annexed eight years ago. The attack on the Kerch Bridge damaged an important supply route for the Kremlin’s forces, and was a blow to Russian prestige.

Recent fighting has focused on the regions just north of Crimea, including Zaporizhzhia. Ukrainian President Volodymyr Zelenskyy lamented the latest attack in a Telegram post.

“Again, Zaporizhzhia. Again, merciless attacks on civilians, targeting residential buildings, in the middle of the night,” he wrote. At least 19 people died in Russian missile strikes on apartment buildings in the city on Thursday.

“From the one who gave this order, to everyone who carried out this order: They will answer,” he added.

Ukrainian Foreign Minister Dmytro Kuleba called the attacks on civilians a war crime and urged an international investigation.

The six missiles used in Sunday’s overnight attack were launched from Russian-occupied areas of the Zaporizhzhia region, the Ukrainian air force said. The region is one of four Russia claimed as its own this month, though its capital of the same name remains under Ukrainian control.

Stunned residents watched from behind police tape as emergency crews tried to reach the upper floors of a building that took a direct hit. A chasm at least 12 meters (40-feet) wide smoldered where apartments had once stood.

In an adjacent apartment building, the missile barrage blew windows and doors out of their frames in a radius of hundreds of feet. At least 20 private homes and 50 apartment buildings were damaged, city council Secretary Anatoliy Kurtev said.

In the immediate aftermath, the city council said 17 people were killed, but later revised that down to 12. Regional police reported on Sunday afternoon that 13 had been killed and more than 60 wounded, at least 10 of them children.

Tetyana Lazunko, 73, and her husband, Oleksii, took shelter in the hallway of their top-floor apartment after hearing air raid sirens. The explosion shook the building and sent their possessions flying. Lazunko wept as the couple surveyed the damage to their home of nearly five decades.

“Why are they bombing us? Why?” she said.

About 3 kilometers (2 miles) away in another neighborhood ravaged by a missile, three volunteers dug a shallow grave for a German shepherd dog killed in the strike, its leg blown away by the blast.

Russian officials did not immediately comment on the strikes. Defense officials have similarly avoided direct mention of the blast that damaged the Kremlin’s prized Crimea bridge.

Some nationalist bloggers have begun to levy rare criticism at Russian Vladimir Putin for failing to address the bridge attack, the Washington-based Institute for the Study of War noted.

Abbas Gallyamov, an independent Russian political analyst and a former speechwriter for Putin, said the Russian president, who formed a committee Saturday to investigate the bridge explosion, had not responded forcefully enough to satisfy angry war hawks. The attack and response, he said, has “inspired the opposition, while the loyalists are demoralized.”

“Because once again, they see that when the authorities say that everything is going according to plan and we’re winning, that they’re lying, and it demoralizes them,” he said.

Putin personally opened the Kerch Bridge in May 2018 by driving a truck across it as a symbol of Moscow’s claims on Crimea. The bridge, the longest in Europe, is vital to sustaining Russia’s military operations in southern Ukraine.

No one has claimed responsibility for damaging it.

Traffic over the bridge was temporarily suspended after the blast, but both automobiles and trains were crossing again on Sunday. Russia also restarted car ferries service.

Crimea is a popular vacation resort for Russians. People trying to drive to the bridge and onto the Russian mainland on Sunday encountered hours-long traffic jams.

“We were a bit unprepared for such a turn,” said one driver, Kirill Suslov, sitting in traffic. “That’s why the mood is a bit gloomy.”

The Institute for the Study of War said videos of the bridge indicated the damage from the explosion “is likely to increase friction in Russian logistics for some time” but not cripple Russia’s ability to equip its troops in Ukraine.

Hours after the explosion, Russia’s Defense Ministry announced that the air force chief, Gen. Sergei Surovikin, would now command all Russian troops in Ukraine.

Meanwhile, the Ukrainian military said Sunday that fierce clashes were taking place around the cities of Bakhmut and Avdiivka in the eastern Donetsk region, where Russian forces have claimed some recent territorial gains. The General Staff of the Armed Forces of Ukraine did not acknowledge any loss of territory but said “the most tense situation” had been observed around those two cities.

And in the devastated Ukrainian city of Lyman, which was recently recaptured after a months-long Russian occupation, authorities were searching for the bodies of more civilians. Mark Tkachenko of the Kramatorsk district police said Lyman has become a “humanitarian crisis” that could still hold further grim discoveries like mass graves.