Expert speaks out following helicopter crash: What could have caused the accident? VIDEO

Four Italian nationals were killed in the accident on Thursday: two soldiers and two members of the Military Red Cross. Italy's Ambassador to Bosnia and Herzegovina said the helicopter crashed during takeoff, while the official cause of the accident has yet to be determined.

"An exclusively technical failure. No human error whatsoever, purely a technical malfunction. You can see that the person was trying to react as best they could, but it was entirely due to a technical failure," Kulić said.

According to him, the pilot was unable to do anything at that moment.

"There was nothing he could have done in that situation. Helicopter specialists will be better placed to explain the exact technical malfunction, but human error was certainly not the cause," he said.

Kulić explained that takeoff is the most sensitive phase of a flight.

"In aviation, takeoff is always the most critical phase. Once an aircraft is airborne, it has to land. Pilots train for years and practise this every day, so they will manage to land one way or another, unless a sudden technical failure occurs. During takeoff, however, the aircraft is transitioning from a stationary position to flight, which is generally the most critical moment," Kulić stressed.