All 176 passengers and crew onboard a Ukraine International Airlines flight which crashed shortly after takeoff from Imam Khomeini Airport in Tehran have died, said a report.

According to a report in CNN, the Boeing 737 suffered technical difficulties after it took off. Earlier reports from Iranian state media had said 180 people were on board.

The Ukrainian Embassy in Tehran said it has ruled out terrorism as a cause of the crash and that preliminary information shows it was caused by an engine malfunction.

Emergency crews were dispatched to the crash site but could not assist because the area was ablaze, Pirhossein Koulivand, the head of Iran's Emergency Medical Services said on IRINN, a state-run media outlet.

Flight-tracking service FlightRadar 24 said in a tweet that the jet had been in service for about three and a half years.