South Korean officials say a 16th century royal seal in the collection of the Los Angeles County Museum of Art may have been stolen out of a shrine in Seoul during the Korean war.
An official at the state-run cultural heritage administration said that South Korea in May asked the United States to investigate how the gilt bronze seal ended up at the museum in 2000.
The official, who spoke on condition of anonymity, says US officials have confiscated the seal from the museum.
The Royal Seal of Queen Munjeong has a square stamp and a handle in the shape of a turtle.
The Los Angeles Times says the Korean government has long thought similar signets from the Joseon Dynasty that went missing after the war were stolen by US soldiers.