This undated file photo released by the St. Louis Art Museum, shows the burial mask of Ka Nefer Nefer at the St. Louis Art Museum in St. Louis. Egyptian records seen by the AP show the burial cover for Ka Nefer Nefer's mummy was discovered in 1952 by Ghoneim, who oversaw excavations at the Saqqara pyramids, about 12 miles south of the more famous Great Pyramids of Giza. It resurfaced in 1998 when the St. Louis Art Museum acquired it. And now it is at the center of one of the most acrimonious fights in the antiquities world.

CAIRO, Egypt — More than half a century ago, a prominent Egyptian archeologist unearthed a stunning ancient mummy mask at the Saqqara pyramids near Cairo — the golden image of a noblewoman's face.

Mohammed Zakaria Ghoneim deposited the 3,200-year-old relic in a warehouse at Saqqara, where he meticulously documented his discovery. Seven years later, in 1959, Egyptian records show it was still in the same storeroom.

What happened to the burial mask of Ka Nefer Nefer in the four decades that followed is a mystery.

It resurfaced in 1998 when the St. Louis Art Museum acquired it. And now it is at the center of one of the most acrimonious fights in the antiquities world.

The case lays bare the complexities involved in growing efforts by Egypt and other countries to reclaim artifacts stolen or looted from their ancient civilizations.

Claims are attracting increasing attention after prestigious institutions such as the J. Paul Getty Museum of Art in Los Angeles and the Metropolitan Museum of Art in New York agreed to return looted or stolen artwork or antiquities. Zahi Hawass, head of Egypt's antiquities authority, said his country has recovered some 5,000 stolen artifacts since 2002, and is pursuing dozens more.

"This is the No. 1 case," he told The Associated Press in an interview. "Egypt has a right to the mask."

Hawass said there is no record showing the mask ever left Egypt legally. But the St. Louis museum contends Egypt has not proven it was stolen.

"That is a charge we took very seriously," museum director Brent Benjamin told the AP. "If that is true, there is no question that the museum would return the object," he said.

Egyptian records seen by the AP show the burial cover for Ka Nefer Nefer's mummy was discovered in 1952 by Ghoneim, who oversaw excavations at the Saqqara pyramids, about 12 miles south of the more famous Great Pyramids of Giza.The sprawling necropolis of Saqqara is the burial site of the rulers of ancient Memphis, the capital of Egypt's Old Kingdom. Ghoneim found the mask in a burial site behind the unfinished Step Pyramid of King Sekhemkhef. The funerary cover was inside, dating from 1307-1196 B.C.Ghoneim registered his find in the official ledger at the government warehouse, or magazine, at Saqqara. The page in the ledger book, a key document Egypt has presented to St. Louis to stake its claim, shows a high-quality photograph of the mask, the finder's name and ID number, and a detailed description.In 1957, Ghoneim published his discovery in a book showing him and the mask at the site, which Egyptologists view as important evidence for Egypt's claim.A second record from Saqqara given to St. Louis showed the artifact was packed in a box with other antiquities in 1959 for a shipment to the Egyptian Museum in Cairo.Around that time, Egypt was beginning to exhibit its antiquities abroad and the mask was considered important enough for a show planned for Japan. But Egypt says the mask never made it there.

Zahi Hawass head of Egypt's antiquities authority, said his country has recovered some 5,000 stolen artifacts since 2002, and is pursuing dozens more. One item Hawass has targeted is the burial mask for Ka Nefer Nefer's mummy. The whereabouts of the mask were unknown for decades. It resurfaced in 1998 when the St. Louis Art Museum acquired it. It has since become the center of one of the most acrimonious fights in the antiquities world.