The aircraft, owned by a Moldovan company, was carrying 14 people including 11 members of Afghan security forces when it crashed in the northern province of Balkh, the Moldovan aviation authority said in a statement.
The two Ukrainians killed were crew members, the statement said. A third Ukrainian crew member survived the crash.
An Afghan security source confirmed the death toll. Another Afghan security source put the death toll at 13, with only the foreign pilot surviving the accident.
The helicopter was carrying munitions and exploded on impact, burning bodies “beyond recognition”, the Afghan sources said.
Afghan officials earlier put the death toll at three.
The helicopter crashed due to “technical problems” shortly after taking off in Dehdadi district, Nazer Khuda Pamiri, deputy commander of Afghan forces in northern Afghanistan, told AFP.
It was transporting Afghan security forces from a military base to the volatile northwestern province of Faryab.
The helicopter caught fire after it hit the ground, Pamiri confirmed.
Defence ministry deputy spokesman Mohammad Radmanish said the helicopter belonged to a private company and had been hired by the ministry.