The pilots ejected safely from their planes, Russian-built Su-25 jets, but their conditions were not immediately made available. The incidents occurred near the town of Dmytrivka, the military press office announced.
Pro-Russian separatists in eastern Ukraine have been accused of shooting down Malaysia Airlines Flight 17, a commercial airliner, on July 17, leading to the loss of 298 lives. Ukraine reported two other planes, an Antonov An-26 transport plane and another Su-25 fighter jet -- both military planes -- were shot down days earlier.
The loss of two more fighter jets is seen as a blow to Ukraine's air force, which has a limited number of airworthy planes.