[Read more about the humanitarian crisis in Yemen.]

In an effort to recover some of the items, Yemeni officials visited Washington and New York in recent days to ask the Trump administration and the United Nations to help them forestall the scattering of a heritage that stretches back nearly 4,000 years. Their central request is that the United States issue an emergency order that would bar the import of Yemeni artifacts that did not carry special documentation.

Typically, antiquities from abroad cannot enter the country without documentation mandated in one-on-one agreements between the nation of origin and the United States. Because Yemen is not party to any such agreement, its artifacts simply need to be declared at customs in a routine way.

The Saudi-backed Yemeni government hopes the United States will impose new rules requiring importers to show proof that the objects had been legally obtained. That proof could be in the form of a government authorization or documents proving that the items had a well-established provenance trail dating from before the civil war.

“Yemen was a cradle to many civilizations and a home to multiple faiths, particularly Judaism, Christianity and Islam, which all thrived here,” Yemen’s culture minister, Marwan Dammaj, said in New York on Wednesday. He denounced the pillaging as “a gross affront to humanity at large.”