Egyptian President Abdel-Fattah al-Sisi on Sunday said there was immediately no firm assumption as to why the Egyptair plane crashed into the Mediterranean Sea last week.
"All assumptions are possible," Xinhua news agency quoted Sisi as saying.
"Reaching the reasons behind the plane crash takes long time … we will announce the results once we finish investigating," Sisi said.
On Thursday, EgyptAir said its flight MS804, operated by an Airbus A320, disappeared from radar screens en route from Paris to Cairo at 2.45 a.m. (local time).
Also on Thursday, Egypt’s Civil Aviation Minister Sherif Fathy said a terrorist attack was more likely than a technical failure as the cause of the crash.
The plane had 66 people aboard, including 56 passengers — 30 Egyptians, 15 French, two Iraqis and nine others each from Algeria, Belgium, Portugal, Britain, Canada, Chad, Kuwait, Saudi Arabia and Sudan.