A representative of the Emergency Situations Ministry said the accident happened Wednesday night. The truck, carrying servicemen of a paratrooper unit stationed in Tula, swerved off a road and rolled onto its side near the town of Serebryannye Prudy, east of Moscow.
"There are 21 people in the hospital across the region now, and two others have been transferred to the Vishnevsky and the Burdenko military hospitals [in Moscow]," the official said Thursday.
Investigators are probing what may have caused the accident. Their main theory is careless driving.