Four people have been arrested in Turkey in connection with the deaths of two Dutch teenage brothers who fell ill after an evening out in Istanbul.

The brothers, aged 15 and 17, were found dead in their hotel room, where they were staying with their father, on August 21.

Hotel staff found their bodies when they went into the room after the family failed to check out. The man was taken to hospital in a critical condition suffering from shock, but has since stabilised.

According to Turkish media, the father said his sons had had food and drink at two different restaurants in the area of Taksim Square, but it is not clear if they suffered food poisoning. There were no indications they had been attacked.

On Monday the owners and two staff at the restaurants were reported to have been arrested. Food and drink samples from both establishments have been sent to a forensic laboratory for analysis.