Illia Yevlash, the head of the press service of the Eastern Group of the Ukrainian Armed Forces, shared the information with RBC-Ukraine.
"There was a crash involving two Mi-8 helicopters. They were on a combat mission. While they were performing the mission, an enemy Su-35 fighter jet was in the air," he told reporters.
The helicopters may have crashed while attempting to land to avoid being targeted by enemy Su aircraft.
Yevlash mentioned that the information regarding the number of casualties needs further clarification.
"But the head of the press service of the 18th separate army aviation brigade has already reported that there were six of them," said Yevlash.
He added that investigators are currently establishing the details and circumstances of the tragedy.
"The commission is working now. What caused the crash will be known later," Yevlash summarized.
On August 25, two L-39 combat trainer aircraft collided in the sky in the Zhytomyr region during a combat mission, killing three pilots of the Ukrainian Air Force.
The State Bureau of Investigation is studying three possible versions of the crash in the Zhytomyr region, which killed Ukrainian pilots.