A Ukrainian missile strike hit the bridge connecting Russian-held parts of the southern Kherson region with the annexed Crimea peninsula, officials said on Thursday.
The attack forced traffic to be diverted to a different route, according to the Russia-appointed officials in both regions.
Vladimir Saldo, the Russia-appointed Kherson governor, said the road was damaged but no casualities were reported.
He claimed British-supplied Storm Shadow missiles were likely to have been used for the attack.
This could not be independently verified and may be an attempt to blame the West for the strike.
Crimea's governor, Sergey Aksyonov, said specialists were examining the site to determine when traffic over the bridge could resume.
Known as "the gate to Crimea", the Chongar bridge is one of a handful of bridges linking Crimea - which was annexed by Russia in 2014 - with the mainland.
The bridges provide an alternative to the narrow isthmus connecting the peninsula and the continent.
Taking control of the region from the west coast of the Sea of Azov to the east bank of the Dnipro river, has been one of Moscow's few successes so far in the war, as it meant Crimea was no longer cut off from other Russian-held territory.
Destroying this links could give Ukraine both an advantage in retaking the peninsula and leverage in any future negotiations.
Ukrainian officials, in turn, reported a drone attack overnight on the port city of Odesa, where a warehouse was destroyed.
Missiles also struck and a residential area in the central Kryvyi Rih region, and there was shelling and bombing along the frontlines, they said.
Ukrainian troops had partial success in the direction of Rivnopil and Staromayorske in the Donetsk region, and were holding on to their gains, said Andriy Kovalev, a spokesman of the General Staff of the Armed Forces of Ukraine.
In the Lyman direction, Ukrainian units also mounted offensive actions in the direction of the settlements of Bilogorivka and Dibrova, Kovalev said, adding that they had achieved partial success, and had dug in to hold onto their gains.
Ukrainian troops were also reportedly resisting Russian attacks in the areas of Lyman, Bakhmut, Avdiivka and Mariynka.
"Particularly heavy fighting continues in the Lymansky direction in the areas northwest of Dibrova, near Serebryansk forestry and north of Hryhorivka in the Donetsk region," according to a military source.
President Volodymyr Zelensky said on Wednesday that progress in Ukraine’s counter-offensive against Russian forces was “slower than desired”, but Kyiv would not be pressured into speeding it up.
“Some people believe this is a Hollywood movie and expect results now. It’s not,” he told the BBC.
“What’s at stake is people’s lives.”
He said Ukrainian troops were advancing on the southern front and holding defence lines in the east, long the focus of Russia’s nearly 16-month-old campaign.
The Institute for The Study of War also stressed that Kyiv had laid the ground to step up its offensive.
The Washington-based think tank tweeted: “The overall slower-than-expected pace of Ukrainian counter-offensive operations isn’t emblematic of Ukraine’s wider offensive potential, & Ukrainian forces are likely successfully setting conditions for a future main effort despite initial setbacks.”
Vladimir Putin said Moscow had observed a “lull” in Ukraine’s counter-offensive, which began early this month.
