New questions have arisen in the search for the cause of Wednesday's air crash in Madrid which killed at least 153 people, it emerged on Friday.

Contrary to the early assumption that the aircraft had been downed by an engine catching fire on take off, video footage released by the Spanish national airport company AENA on Friday showed that neither a fire nor an explosion were evident in the plane's engines prior to the crash.

"The plane caught fire only after it hit the ground," the Spanish daily El Pais reported.

Investigators continue to look for evidence of causes of the crash.

"There was more than one cause. An engine was not the cause of the accident," El Pais quoted AENA chief Manuel Battista as saying.

Nineteen people, most of whom sustained severe injuries, survived the crash which was the worst air disaster in Spain for 25 years.