Russian authorities said Saturday that a Ukrainian attack on the city of Belgorod had killed at least 20 people and injured more than 110 others, in what would be the deadliest single assault against a Russian city since the start of the war nearly two years ago.

Russia’s Defense Ministry said in a statement that Ukraine had hit Belgorod — a regional center of around 330,000 residents about 25 miles north of the Ukrainian border — with two missiles and several rockets, adding that the strike was "indiscriminate.”

The ministry said that most of the rockets had been shot down but that some debris had fallen on the city. The Ukrainian government has not officially commented on the Belgorod attack, and Russian claims could not be independently verified.