Zaporizhzhia, Ukraine - A Russian missile attack on residential buildings in the southern Ukrainian city of Zaporizhzhia has left 12 dead and 49 injured, including six children who required hospitalization, Ukrainian President Volodymyr Zelensky said on Sunday.

He spoke of "absolute evil," saying the "terrorists" would be held accountable, as he published pictures of buildings that had been largely destroyed on his Telegram channel.

Although Russian troops control much of the region of Zaporizhzhia, the city of the same name remains under Ukrainian control, despite continued attacks by Moscow's forces.

Russian troops fired at least 12 rockets at the residential buildings, according to Ukrainian military sources.

Moscow did not confirm the attack. The Ukrainian authorities had initially given a higher death toll during the night, but then revised it downwards.

Russia is trying to make further advances in Zaporizhzhia, one of the four Ukrainian territories Moscow has annexed, prompting an international outcry.

Meanwhile, Ukraine has liberated dozens of villages in its continuing counteroffensive, as the Russian invasion flounders.

The attacks on Zaporizhzhia came hours after an explosion severely damaged a bridge to Crimea on early Saturday. The blast sent smoke and flames into the air, tearing apart one of the key supply routes for Moscow's faltering military campaign in Ukraine.

Investigations are under way into the blast, but a Ukrainian source told The New York Times that the country's intelligence service was behind the attack.

The bridge connecting mainland Russia to the occupied Crimean peninsula was opened by Russian President Vladimir Putin himself in 2018.

On Sunday, Britain's Defense Ministry said while traffic had partly resumed, the bridge's capacity would be "seriously degraded."

"The extent of damage to the rail crossing is uncertain, but any serious disruption to its capacity will highly likely have a significant impact on Russia’s already strained ability to sustain its forces in southern Ukraine," the ministry said.

The line has played a "key role in moving heavy military vehicles to the southern front during the invasion," the intelligence update added.

The blast will likely touch Putin closely, the defense analysts wrote, noting that it came hours after his 70th birthday.

"He personally sponsored and opened the bridge, and its construction contractor was his childhood friend, Arkady Rotenberg," the ministry noted.