The blast occurred during a meeting on Saturday of Russian officers in the city, a hub of Russian forces in the south, the directorate within the defense ministry said in a statement.
“This act of revenge, carried out by representatives of the local resistance, took place in Nova Poshta offices seized by the Russians,” it said, referring to the premises of a popular Ukrainian courier service.
There was no mention of the incident from Russian officials. Reuters was unable to verify the Ukrainian statement.
The intelligence statement said the meeting on Saturday at the local military headquarters was attended by Russian National Guard and FSB intelligence service officers.
“As a result of the explosion at least three National Guard officers were killed at the headquarters,” the statement said. “Information of other enemy losses is being clarified.”
The statement said police converged on the area and a burned-out car was later seen being towed through the town.
Russia began a full-scale invasion of Ukraine in February 2022. Ukraine launched a counteroffensive in the south and east in early June but has encountered strong resistance.
Ukraine’s military has been increasingly active in attacking forces in Russian-held areas but does not always acknowledge the strikes.
Ukrainian forces staged a missile attack on the Black Sea Fleet headquarters in Russian-annexed Crimea in September. Ukrainian media said an attack last week on the occupied town of Skadovsk in Kherson region also targeted Russian officers.