The Ukrainian military also confirmed the attack, saying that there were dozens of casualties.

The strike came after an explosion Saturday caused the partial collapse of a bridge linking the Crimean Peninsula with Russia, damaging an important supply artery for the Kremlin’s faltering war effort in southern Ukraine and hitting a towering symbol of Russian power in the region.

Zaporizhzhia has been repeatedly hit in recent weeks and is in the Ukrainian-controlled part of a region that Russian President Vladimir Putin annexed in violation of international law last week.

A part of the region currently in Russian control is home to the Zaporizhzhia nuclear power plant, Europe’s largest. It has repeatedly been imperilled by fighting, and lost its last remaining external power source as a result of renewed shelling, the UN nuclear watchdog said Saturday. It is now relying on emergency diesel generators.

No one has claimed responsibility for the Crimea bridge attack, but it was a significant blow to Russia and could lead to an escalation of the conflict. Some Russian lawmakers are calling for Putin to declare a “counterterrorism operation,” rather than the term “special military operation” that has downplayed the scope of fighting to ordinary Russians.

Putin signed a decree late Saturday tightening security for the bridge and for energy infrastructure between Crimea and Russia, and put Russia’s federal security service, the FSB, in charge of the effort.

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.

Surovikin, who this summer was placed in charge of troops in southern Ukraine, had led Russian forces in Syria and was accused of overseeing a bombardment that destroyed much of Aleppo.

The 19-kilometer (12-mile) Kerch Bridge, on a strait between the Black Sea and the Sea of Azov, is a symbol of Moscow’s claims on Crimea and an essential link to the peninsula, which Russia annexed from Ukraine in 2014.

The $3.6 billion bridge, the longest in Europe, is vital to sustaining Russia’s military operations in southern Ukraine. Putin himself presided over the bridge’s opening in 2018.

Ukrainian President Volodymyr Zelenskyy, in a video address, indirectly acknowledged the bridge attack but did not address its cause.“Today was not a bad day and mostly sunny on our state’s territory,” he said.

“Unfortunately, it was cloudy in Crimea. Although it was also warm.”

Zelenskyy said Ukraine wants a future “without occupiers. Throughout our territory, in particular in Crimea.”

Zelenskyy also said Ukrainian forces advanced or held the line in the east and south, but acknowledged “very, very difficult, very tough fighting” around the city of Bakhmut in the eastern Donetsk region, where Russian forces have claimed recent gains.

Train and automobile traffic over the bridge was temporarily suspended. Automobile traffic resumed Saturday afternoon on one of the two links that remained intact, with the flow alternating in each direction, said Crimea’s Russia-backed leader, Sergey Aksyonov.

Rail traffic was resuming slowly. Two passenger trains left the Crimean cities of Sevastopol and Simferopol and headed toward the bridge Saturday evening. Passenger ferry links between Crimea and the Russian mainland were being relaunched Sunday.

While Russia seized areas north of Crimea early in its invasion of Ukraine and built a land corridor to it along the Sea of Azov, Ukraine is pressing a counteroffensive to reclaim that territory. That Russian-held territory along the sea includes the Zaporizhzhia region.

The Crimean Peninsula is a popular destination for Russian tourists and home to a Russian naval base. A Russian tourist association estimated that 50,000 tourists were in Crimea on Saturday.