Hawass told National Geographic News "it will be a scientific war" if Germany refuses to loan the iconic artwork.
The antiquities chief also said he would organize a worldwide boycott of loans to German museums if the request is denied.
Meanwhile, Egypt's Ministry of Culture says it will mail official letters to France, Germany, Great Britain, and the United States this week to request the temporary loans.
Hawass said Egypt will deal with each museum on an individual basis.
"If a museum cooperates with us, then we will continue our good relations and cooperate with them in a mutually beneficial, scientific manner," he said.
Hannah Boulton, a spokesperson for the British Museum, said that the museum will wait for the letter before commenting in detail and that museum policy is to consider any request.
She added, however, that any such loan would only be temporary.
"Obviously a precondition of the loan from the museum's collections is the recognition that the ownership is rested within the British Museum," she said.
Messages left with the Altes Museum and with two other institutions being asked for loans—the Louvre in Paris, France, and the Museum of Fine Arts in Boston, Massachusetts—went unreturned.
Hawass, who champions the repatriation of Egyptian artifacts, has previously called for the permanent return to Egypt of all five items on the list for temporary loans.
(Read "Egypt's Antiquities Chief Combines Passion, Clout to Protect Artifacts" [October 24, 2006].)
The requested items include:
Nefertiti's bust at the Altes Museum. The painted limestone likeness of the Egyptian queen has been in Germany since 1913, a year after German archaeologists discovered it at a site 150 miles (240 kilometers) south of Cairo.
The Rosetta Stone at the British Museum. The writing in three languages on the 1,600-pound (726-kilogram) slab of rock was essential to deciphering Egyptian hieroglyphics.
The Zodiac ceiling from the Dendera Temple at the Louvre in Paris. Archaeologists consider the zodiac an Egyptian representation of the astrological calendar.
The statue of Hemiunu, an architect of the Great Pyramid, at the Roemer-Pelizaeus Museum in Hildesheim, Germany.
The statue of Ankhaf, builder of the Chephren Pyramid, at the Museum of Fine Arts in Boston.
Hawass said the current requests for temporary loans of the five items are sincere.
"The temporary return of artifacts from museums in Europe and the United States will allow Egyptians who do not travel the opportunity of seeing wonderful masterpieces," he said.
"I believe that our request for the return of these artifacts temporarily is a fair one."
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