Egypt has asked an art museum in the US to return a 3,000-year-old funerary mask it claims disappeared from the capital's Egyptian Museum decades ago.
The mask was discovered in 1952 in the step pyramid at Saqqara
The piece, known as the mask of Ka Nefer Nefer, is said to date back to the 19th Dynasty, 1307-1196BC.
Egypt's Supreme Council of Antiquities said the mask was discovered in 1952 in the pyramid at Saqqara, near Cairo.
It is thought to have been smuggled abroad before being bought by Missouri's St Louis Art Museum in 1998.
"The mask is in a very well preserved condition and it features the bust of a young lady called Ka Nefer Nefer," said Egypt's antiquities chief Zahi Hawass.
"It has a combination of glass inlaid eyes, a face covered with gold and a wig."
The mask was stored at the Saqqara site until 1959, when it was taken to the Egyptian Museum in the capital, Cairo.
Poor storage and a primitive documentation system used at the museum at the time are believed to have facilitated the mask's "disappearance" until it surfaced on the American market and was bought in 1998.
Jennifer Stoffel, a spokesperson at the St Louis Art Museum, confirmed they had received the request from Egypt.
"We have written back asking for more information and included our research.
"We would like to come to a solution because we don't think that it was obtained illegally or improperly," she said.
Egypt's antiquities council has also asked the Basel Museum in Switzerland to return the left eye of a statue of King Amenhotep III, which it said was stolen from a temple in Luxor several years ago.