According to prosecutors, Russian forces in the Belgorod region north of Kharkiv fired S-300 missiles, two of which hit a warehouse.
“Analysis of the debris continues at the scene to determine the exact number of injured and dead,” Dmytro Chubenko, a spokesman for the agency, told Ukrainian state broadcaster Sasypirne.
At least two people were killed in separate Russian attacks on villages near the war-torn Ukrainian city of Bakhmut on Sunday, officials said.
Both Kiev and Moscow are preparing for a harsh winter as Ukraine warns of new attacks on its energy infrastructure and Russia looks to retake territory in a Ukrainian counterattack.
In a speech Sunday night, President Zelenskiy said that in the eastern Donetsk region, Ukrainian positions around the frontline city of Avdiivka were “secured.”
The city has been the center of intense fighting in recent weeks as both sides struggle to advance. Ukraine’s General Staff announced Friday that Russia is intensifying its military offensive on Avdiivka in a continuing effort to surround and occupy the city.
“The direction of Avdiivka and Marinka is particularly difficult,” Zelenskiy said. “Numerous attacks by the Russians. But our position will be defended.”
Avziivka has been a symbol of Ukrainian resistance since 2014, after briefly falling to Russian-backed separatists.
The city is just 15 kilometers (9 miles) from the Moscow-controlled city of Donetsk, the capital of the Donetsk region, which Russia announced last September that it would annex it.
Ukrainian soldiers were preparing for a new attack after a failed three-pronged Russian attack using columns of armored vehicles and tanks earlier this month.
Avdiivka was built around a huge coke factory and had a pre-war population of around 30,000 people.
According to local authorities, about 1,600 people are still living in basements that have been converted into air raid shelters.
The city center was nearly destroyed by daily Russian artillery shelling and a months-long air campaign.
Also on Sunday, Russian officials said the Russian military shot down three missiles that targeted the Crimean Peninsula, which Russia annexed from Ukraine in 2014.
The peninsula is crucial for Russian attacks, both for resupplying southern Ukraine and for launching missile attacks from the sea.
It has become a regular target for Kiev, and attacks on military facilities there have intensified as Ukraine vows to retake the peninsula.
“Three enemy missiles heading towards Crimea were shot down” in the Kherson region, Russian government official Vladimir Sardo said on Telegram.
Ukraine announced on Sunday that it had destroyed a guided missile and three drones fired by the Russian military.
Last month, Ukraine launched an unprecedented missile attack on its naval headquarters on the peninsula.
Moscow said one Russian service member was missing after the attack, which heavily damaged buildings, while Kiev claimed more than 30 officers were killed in the attack.