A 3,300-year-old sculpture of Tutankhamen’s head sold for almost $6 million at auction, defying calls from Egyptian authorities for the artifact to be returned to its native country.

Auction house Christie’s said the “rare, beautiful and important work” achieved a price of £4,746,250 ($5,968,058) in London on Thursday, where it was purchased by an unnamed buyer.

The 11-inch artifact, carved from brown quartzite, portrays the Ancient Egyptian “Boy King” wearing the crown of the god Amun.

Christie’s went ahead with the auction despite demands from Egypt for the relic to be returned.

“I believe that it was taken out of Egypt illegally ... (Christie’s) have not presented any documents to prove otherwise,” Mostafa Waziri, secretary-general of Egypt’s Supreme Council of Antiquities, told Reuters before the auction.

He reportedly added that Egypt would press the buyer for the sculpture to be returned.

A spokesperson for Egypt’s Ministry of Antiquities was not immediately available for comment when contacted by CNBC.

Christie’s did not immediately respond to a request for comment, but in a press release Thursday the auction house said: “We recognize that historic objects can raise complex discussions about the past; yet our role today is to work to continue to provide a transparent, legitimate marketplace upholding the highest standards for the transfer of objects.”

“We believe it is in the public interest that works come out into the open with the opportunity for them to be researched, as well as seen and enjoyed by global audiences,” the statement continued.

Prior to the sale, the relic had been kept as part of a German art collection since 1985. It had previously been owned by German aristocrat Prinz Wilhelm von Thurn.

Tutankhamen, one of Egypt’s most famous kings, ruled for nine years and died before his 20th birthday. His tomb was discovered in 1922 by British archaeologist Howard Carter with its contents intact.

Earlier this year, British authorities returned an ancient artifact to Egypt that had been illegally smuggled out of the country and was headed for auction.