The Los Angeles County Museum of Art has bid dasvidaniya to about 30 artworks that Russian authorities had promised as loans to "Gifts of the Sultans: The Arts of Giving at the Islamic Courts," then withheld. Russia has imposed an embargo on all loans to American museums in a display of its displeasure over a U.S. legal decision that has nothing to do with art or museums.

That has left LACMA curators and exhibit installers to practice the art of improvisation as they rejigger the show's layout to avert any discernible voids in the presentation when the show opens Sunday with more than 200 other objects from the museum's own collection or loaned by a wide array of non-Russian sources.

One of the artworks, an 18th-century Turkish tent embroidered in silk and gold that had been a gift to Catherine the Great and now belongs to the State Hermitage Museum of St. Petersburg, was to have served as the centerpiece for the show's largest section. Like its companions from the Hermitage and two other Russian collections, it is being held hostage in a standoff involving the Russian and U.S. governments and Chabad, a prominent branch of the ultra-Orthodox Jewish Hasidic movement.

Last year, Chabad won a court victory when a federal judge in Washington ordered Russia to return vast troves of religious books and rabbinic manuscripts seized during the Russian Revolution and World War II. Chabad originated in Russia in the 1700s and was transplanted to the United States during the 20th century.

The Russian government contends that it is not bound by U.S. court decisions concerning what it considers to be its own property.

Consequently, the Houston Museum of Natural Sciences suffered the loss of "Treasures from the Hermitage: Russia's Crown Jewels," which was to have opened last month, "Treasures from Moscow," a show at the Museum of Russian Icons in Clinton, Mass., was shut down in March when orders came for the exhibition to be sent home, and Russia has reneged on loans to the Getty Museum, the Metropolitan Museum of Art and the National Gallery of Art, among others.