Egyptian President Abdel Fattah al-Sisi said an investigation into the causes of Saturday's Russian plane crash in which 224 people were killed could take months.
"This is a complicated matter and requires advanced technologies and broad investigations that could take months," he told army recruits in a televised speech on Sunday.
Sisi urged people to wait for the outcome of an investigation to determine the exact reason the Russian airliner crashed.
The jihadist Islamic State group has claimed it downed the plane on Saturday in Egypt's restive Sinai Peninsula, but experts have expressed extreme doubt over its ability to hit an airliner at cruising altitude.
"In such cases, leave it to specialists to determine the cause of the plane crash because it is a subject of an extensive and complicated technical study," state news agency MENA quoted Sisi as telling a gathering of army officers.
