The co-pilot of flydubai flight FZ1073 attempted to carry out a "terrorist" attack during the flight, the United Arab Emirates prosecutor general said on Saturday, according to the state news agency WAM.
The co-pilot attacked the pilot inside the cockpit with a crash axe and attempted to take control of the aircraft, the prosecutor general said.
A crash axe is typically kept in the cockpit for use during emergencies such as crashes.
Investigations are ongoing to determine the circumstances of the incident, the motives and any related connections, as well as to examine physical and digital evidence, he added.
UAE Prosecutor General Hamad Saif Al Shamsi's comments were the first by Emirati authorities to describe the incident as an attempted "terrorist" attack.
Disaster was averted on Wednesday after passengers and crew subdued the co-pilot, who had attacked the captain.
A reserve flydubai pilot travelling on the flight took control of the aircraft and landed it at Tabuk airport in northwestern Saudi Arabia, where the co-pilot was detained by Saudi authorities.
Flydubai said the circumstances surrounding the incident were still under investigation and that it was not in a position to comment further, a spokesperson said.