FILE PHOTO: The Thomas Cook logo is seen in this illustration photo January 22, 2018. REUTERS/Thomas White/Illustration/File Photo

CAIRO (Reuters) - The air conditioning system at a hotel where a British couple died in unknown circumstances while on holiday in Egypt is sound, the public prosecutor said on Saturday, citing a report by engineering experts.

The prosecutor’s office said it was still waiting for a medical report to determine what caused the death of John and Susan Cooper who passed away hours apart on Tuesday while staying at the Steigenberger Aqua Magic Hotel in Egypt’s popular Red Sea resort of Hurghada.

Britain’s Thomas Cook, which organized the trip, said on Friday it had received further reports of illness among guests at the hotel, without elaborating.

The hotel said on Friday that there had not been a rise in cases of illness.

In a statement, the Egyptian public prosecutor said that engineers assigned to check the room where the deceased couple had been staying concluded that “all equipment was sound and that there was no leakage or emission of any poisonous or harmful gases”.

“All equipment was working properly and had no faults,” it added.

But the statement said the prosecution was still awaiting the results of a forensic analysis of samples taken from the couple, and promised to issue a detailed report.

Egyptian officials said on Friday that both deaths were from heart failure, but the public prosecutor said the cause was still not yet clear.

The deaths come as Egypt is trying to revive tourism, a crucial source of income, while the economy is still struggling from the years of turmoil that followed a 2011 popular uprising.