Fourteen pieces of American art purchased by Iran nearly four decades ago, but blocked for export from the United States because of the 1979 Iranian revolution and rupture in relations, have finally been delivered, both nations said Friday.

Delivery of the art, described by American officials as architectural drawings bought in 1978 by the Tehran Museum of Contemporary Art, came against the backdrop of a slightly improved atmosphere in the estranged ties between Iran and the United States since the agreement resolving Iran’s disputed nuclear work was reached in July.

But neither side portrayed the art delivery as having anything to do with any possible broader reconciliation. Iran’s government, which took the unusual step of announcing the delivery, portrayed it as a partial vindication of a much deeper historical grievance with the United States over impounded property.

American officials, who appeared to have been taken by surprise at the Iranian announcement, said the art delivery was the outcome of a claim filed by the Iranians two years ago with a tribunal created in 1981 under an agreement known as the Algiers Accords.