"On average, the losses are great. They lost six tanks in a massive attack close to [the village of] Rabotyne," Shoigu told reporters in Sochi.
The defense minister said the destroyed tanks had not been imported from the West.
Russian President Vladimir Putin hosted his Turkish counterpart, Recep Tayyip Erdogan, in the Russian resort city on Monday. Shoigu said the Russian leader was right to call the Ukrainian counteroffensive a failure.
"It would probably be wrong for me to comment on the commander-in-chief's words but I can confirm that it is indeed [a failure]," Shoigu said.
Ukrainians have been using large forces to launch fierce attacks against Russian positions in the past 10 days, the minister said, adding that Kiev lost seven underwater drones in the past five days.