Ahmed el-Ashry and his wife Reham Mosad, were looking forward to being reunited with their three children Facebook

A young husband and wife, who were returning from Paris where the mother-of-three had undergone successful cancer treament , were among those killed on board EgyptAir MS804, leaving their children orphans.

The children, who are all under the age of six, were waiting at Cairo International Airport, expecting to be reunited with their parents, Ahmed el-Ashry and his wife Reham Mosad, who were returning from France after a month away.

The two young girls and their brother were left distraught when their parents failed to return following the crash, in which 66 passengers and crew were killed.

Commenting on the tragic circumstance, a friend of the family, Muhammad El Shennawi said: "The situation is very unfortunate and grievous. It is heart-breaking to see the kids. They were at Cairo Airport to welcome them home. But their dad and mum did not reach Cairo..."

Adding further poignancy to the tragedy suffered by the family, it was revealed that Reham Mosad, 27, had gone to Paris for life-saving medical treatment and had successfully fought a battle with cancer.

According to The Telegraph, father Ahmed el-Ashry, a pharmacist, sold his family's flat and car to raise money to fund the expensive cancer treatment abroad. During their absence, the children were left in the care of their grandmother, Mr el-Ashry's mother. After Mosad was given the all-clear, the parents booked their seats on the doomed EgyptAir MS804 and were looking forward to being reunited with their children and resuming their life together.

Muhammad El Shennawi added: "Ahmed did everything to save his beloved wife. I asked him not to go to Paris for the treatment but to try to find a hospital here in Egypt that could treat her – because of the huge cost.

"But Mosad's mother had recently died and her father was already dead. They spent a month in Paris and then came back on this plane. The children are inconsolable. They were already missing their mother and father because they had been away for a month."

On May 19, the EgyptAir flight went off radar around three-and-half hours after taking off from Charles de Gaulle airport in Paris. It reportedly crashed in the Mediterranean, 20 minutes before it was due to land in the Egyptian capital.

On May 20, Greek officials announced Egyptian search parties had discovered the first credible wreckage from the Paris to Cairo flight. According to the Associated Press, the debris included a body part, two seats and suitcases. which were found 290km (180.2 miles) north of the Mediterranean coastal city of Alexandria.

While the cause of the crash remains unclear, the two leading theories are that there was an explosion on board the aircraft or a major mechanical malfunction. Egyptian authorities have said they believe extremists are to blame for the crash, though no organisation has claimed responsibility for the tragedy.

Investigations are underway to establish any terrorist involvement in the crash of EgyptAir flight MS804. Authorities are scrutinising CCTV footage from Paris' Charles de Gaulle airport and interviewing ground staff to determine whether an airport employee from Paris' Charles de Gaulle airport could have played a part in the tragedy.

There were 56 passengers and 10 crew members on board flight MS804 including 30 Egyptians, 15 French nationals, two Iraqis and one person each from Belgium, Kuwait, Saudi Arabia, Sudan, Chad, Canada, Portugal and Algeria on the Airbus A320. A child and two babies were among the passengers on the doomed flight.