Egypt hired two foreign companies on Wednesday to help locate the black boxes of Egyptair flight MS804, as the search for debris and human remains continued in the eastern Mediterranean Sea.
Egyptian investigators tasked the firms - one French and one Italian - with locating the electronic recording devices, presumed to be sitting on the seabed at a depth of 3 kilometres, Egyptair chairman Safwat Muslim told reporters in Cairo.
"Search operations are under way to collect the remains of the victims and the plane wreckage with the help of some neighbouring countries," Muslim said.
Muslim added that on Tuesday and Wednesday DNA samples had been collected from relatives to help identify the remains of the 66 people who were on board the Airbus A320 when it plunged into the Mediterranean while en route from Paris to Cairo on Thursday.
The relatives have been hosted at a hotel near Cairo airport in order for them to updated on search and investigation, he said.
No distress call was received and Egyptian authorities have said the plane did not make contact with Egyptian air traffic control after passing out of Greek airspace shortly before crashing.
The flight data recorder and cockpit voice recorder - known as the black boxes - will provide crucial information about the plane's final moments.
The searchers are racing against time because the devices' underwater locator beacons only transmit "ping" signals for about 30 days, the typical duration of their battery life.
Muslim said the aircraft had been checked before departing from Paris and that no technical problems had been noticed.
State-owned al-Ahram newspaper published pre-flight documents signed by the pilot before taking off from Charles De Gaulle Airport, also suggesting that there were no maintenance problems at the flight's outset.
A day after the crash, Egyptair announced that wreckage from the jet and some body parts had been recovered from the sea. The airline says that searches for remaining debris and human remains are continuing.
So far, only small body parts, no bigger than the palm of a hand, have been recovered, sources in the Egyptian-led investigation committee told dpa Tuesday.
Speaking in the aftermath of the incident, Egyptian Civil Aviation Minister Sherif Fathy said that the likelihood of a terrorist attack was "far higher than the likelihood that the plane developed a technical failure."
However, Egyptian President Abdel-Fattah al-Sissi has warned against rushing to conclusions as to the cause of the crash.
The disaster came almost six months after a Russian passenger jet broke up in mid-air shortly after take-off from the resort of Sharm el-Sheikh in Egypt's Sinai peninsula, killing all 224 people on board.
Russian authorities said that the incident was caused by a bomb. The Islamic State extremist group, which operates in Sinai, claimed responsibility and published a photograph of a soft drink can which it said had been filled with explosives and smuggled onto the flight.
Egyptian authorities are still investigating that incident.