Italian officials have sent the Metropolitan Museum of Art a formal proposal for an agreement on disputed pieces in the museum’s collection, the Italian cultural minister said yesterday. Italy’s culture minister, Rocco Buttiglione, said he was “cautiously optimistic” that a pact would be reached soon.

The museum said it has yet to receive the proposal, which Mr. Buttiglione said was sent earlier this week. But according to Mr. Buttiglione, the proposal follows a framework developed at a November meeting in Rome between the minister and the director of the Met, Philippe de Montebello.

Under the proposed arrangement, Italy would assume ownership of the pieces and loan them to the Met for up to four years, the maximum currently allowed under Italian law. Once the loans were up, Italy would substitute pieces of “equal value” from its collections, Mr. Buttiglione said.

“I think it is a fair agreement,” the minister said, “and this would give satisfaction both to the demand of the American public to be able to see these wonderful pieces of art, and of the right of the Italian government and the Italian people.”

The formal proposal comes months after Italian officials first demanded the return of several valuable antiquities in the Met’s collection that they said were stolen from the country. The disputed works include the Euphronios krater, a fifth-century B.C.E. vase the Met purchased for $1 million in 1972. It is considered among the Met’s most prized antiquities, and Mr. Buttiglione said it was “one of the most valuable” of the 22 pieces Italy is seeking back.

A spokesman for the Met, Harold Holzer, said Mr. de Montebello proposed the framework for the loan arrangement at the meeting in November, provided that the Italians presentl the museum with evidence it considered “convincing” that the works were illegally excavated. Italian officials have repeatedly pointed to photographic and documentary evidence as proof of their claims, but Mr. Holzer said the Met has not received anything since the meeting shortly before Thanksgiving.

The Italians have pursued an agreement with the Met as two American art dealers, Robert Hecht Jr. and Marion True, are on trial in Rome for conspiring to sell looted art. Ms. True is the former curator of the Getty Museum in Los Angeles, which was an early target of Italian officials investigating stolen works.

Mr. Buttligione said the high-profile nature of Italy’s investigations had led to a shift in public opinion, especially in America. The public, he said, now seems to understand the danger of illegally excavating art.

“They cause tremendous damage, not only to the Italian people, but to mankind in general,” Mr. Buttiglione said. “These kind of illegal excavations destroy a large quantity of the knowledge that we might have if the excavations were properly conducted. The result is a loss for all.”

Though the Italians have alleged that more than 100 stolen antiquities are housed in museums across America, Europe, and Asia, Mr. Buttligione said he remains focused on the Met. “Because if we succeed in making a good agreement with the Metropolitan,” he said, “it may be the basis for similar agreements in other cases.”