LOS ANGELES (AP) ― 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 told the Associated Press that South Korea in May asked the United States to investigate how the gilt bronze seal ended up at LACMA in 2000.

The official, who spoke on condition of anonymity, says U.S. officials have confiscated the seal.

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 American soldiers.

In a statement, LACMA said there was “credible evidence” that its seal was “removed unlawfully” from Korea.