A sweeping United States ban on the import of Etruscan, Greek and Roman artifacts from Italy has been extended for five years, the State Department said yesterday. The ban, part of a broader agreement between the countries on protecting Italy's cultural heritage, has come under scrutiny in recent months as Italy pursues an aggressive campaign to retrieve antiquities from several top American museums. Archaeologists and cultural property experts hailed the original accord, which took effect in 2001, as an effective tool against the looting of archaeological sites. In announcing the extension, the State Department commended recent initiatives by Italy to lend more archaeological material to American museums for longer terms. Its also cited Italian police reports indicating that archaeological looting in Italy remains "a severe problem" and that much of the looted material is destined for the United States. Art dealers have argued that the ban blocks legitimate trading in artifacts that are already well represented in Italian collections. And some museum officials assert that Italy has not increased its cultural cooperation as called for in the pact, known as a memorandum of understanding.