At least 22 people, most of them air cadets, were killed in Ukraine on Saturday after a military plane crashed near the town of Chuhuiv, BBC reported. Two others were critically injured. The government said 27 people were on board.

The plane came down about 2 km from a military airport of Chuhuiv, Ukraine’s emergency ministry officials said. It was carrying cadets from Kharkiv Air Force University and was on a training flight.

The cause of the crash is being investigated. The aircraft caught fire after the crash and was extinguished after one hour.

Kharkiv Regional Governor Oleksiy Kucher said preliminary information suggested that one of the pilots had reported failure in one engine before the crash, but that this should not have been a critical situation, Reuters reported, quoting the Interfax-Ukraine news agency.

A video posted by Ukraine’s Deputy Interior Minister Anton Gerashchenko on Facebook showed the plane in flames lying near a road as thick plumes of smoke billowed up in the night sky.

An eyewitness, who was driving along the road towards Chuhuiv, told Reuters he saw a man in flames running from the plane after it crashed. “Another car stopped behind us,” said Yaroslav, who gave only his first name. “We took a fire extinguisher and ran with another driver to help him.”

“It’s a shock,” Gerashchenko told AFP news agency. “At the moment it’s impossible to establish the cause.”

Ukrainian President Volodymyr Zelensky said he would travel to the region on Saturday. “We are urgently creating a commission to investigate all the circumstances and causes of the tragedy,” he wrote on Facebook.

Chuhuiv is located about 100 km from the front line where Ukraine government forces are fighting pro-Russian separatists. However, there is no suggestion that the crash is linked to the conflict in eastern Ukraine.