"A Su-27UB fighter of the Ukrainian Air Force crashed during a training flight near the village of Ulaniv between Berdychiv and Khmilnyk today, at around 5 p.m. Search and rescue operation is ongoing," the Ukrainian Defense Ministry said in a statement, Censor.NET reports citing Ukrinform.
The accident occurred during the Clear Sky 2018 international exercises.
The General Staff of the Ukrainian Armed Forces reported later that two pilots had been found dead.
"We report with regret that according to the search and rescue group, the bodies of two pilots were found. The circumstances of the incident are being clarified," the General Staff said.
The Ukrainian Armed Forces expressed deep condolences to the families of the victims.
According to Commander of the East Air Force Command Oleh Strutsynskyi , Deputy Commander of Aviation, Deputy Head of the East Air Force Command Ivan Petrenko was killed in the catastrophe of the Su-27 fighter in Vinnytsia region.
The commander told Hromadske TV that Petrenko was a first class pilot and had permission to fly all jets of this type.
"It was an introductory flight, nothing special," Strutsynskyi said.
The commander also noted that all the aircraft had been checked before the exercise kicked off and a jet with malfunction just would not be cleared for flight.
"I can still say nothing about the cause. Witnesses reported seeing the jet flying at a low altitude crashed into the ground and then caught fire," he said.
"He was an experienced pilot which means that the chance of pilot error was very slim," Strutsynskyi added.
Petrenko’s colleagues say he was one of the best pilots ever: "there are 40-50 such pilots at best in entire country." Petrenko also took part in combats in the Russian-occupied Donbas.
Petrenko lived and served in the city of Dnipro for the past year. The 46-year-old was survived by a wife and a daughter.
A U.S. serviceman also died in the accident, according to the United States Air Forces in Europe - Air Forces Africa.
"We have seen reports claiming a U.S. casualty and can confirm a U.S. service member was involved in this incident. It is currently under investigation and we will continue to provide more information as it becomes available," reads the statement.