It has also hired a British law firm to sue the auction house, said Egypt’s committee for antiquities repatriation.
The London-based company sold the brown quartzite head depicting the famous boy pharaoh for more than £4.7m last week.
The committee expressed its “deep dissatisfaction with the unprofessional behaviour” at the sale of Egyptian antiquities without title deeds and proof of the legality of their exit from Egypt.
Christie’s denies any wrongdoing over the sale
In a statement to Sky News, it said: “While ancient objects by their nature cannot be traced over millennia, Christie’s clearly carried out extensive due diligence verifying the provenance and legal title, establishing all required facts of recent ownership.
“We recognise historic objects can give rise to complex discussions about the past; our role today is to continue to provide a transparent, legitimate marketplace upholding the highest standards for the transfer of objects from one generation of collectors to the next.
“Christie’s would not and do not sell any work where there isn’t clear title of ownership and a thorough understanding of modern provenance.”
The Egyptian committee also criticised British authorities for not supporting its claim to the sculpture.
Egypt’s general prosecutor has also asked Interpol to trace any Egypt antiquities sold in other countries and hold them until their title deeds are verified.
