The U.S. Attorney's Office has announced that the family of the late American pipeline billionaire George Lindemann has made a momentous decision to return 33 looted artifacts to Cambodia, a move that is highly appreciated by the Southeast Asian nation.

The collection includes statues of deities, angels and demons from the 10th and 12th centuries from Koh Ker, the ancient capital of the Khmer kingdom, and from the famous Angkor Wat temple, the U.S. Attorney's Office for the Southern District of New York said on Tuesday.

In a statement, it said the family's decision to return the artifacts was voluntary. Lawyers for the Lindemann family did not immediately respond to a request for comment.

Cambodia's archaeological sites suffered widespread looting during civil conflicts from the 1960s to 1990s and its government has spent years pursuing the return of antiquities, some of which it says are on display in American museums.

The United States repatriated 27 smuggled antiquities to Cambodia in 2021, including Hindu and Buddhist statues valued at about $3.8 million and last year returned 30 more including several that were over 1,000 years old.

The artifacts that were held by the Lindemann family are expected to be repatriated later this year, said Bradley Gordon, a lawyer advising Cambodia on the repatriations and head of its investigation team.

He said he understood the Lindemann family had paid more than $20 million for the artifacts.

Cambodia's Ministry of Culture and Fine Arts in a statement said the Lindemann family's decision to return the artifacts set "an excellent and proper example for other museums and private collectors."

In a June speech to the American Chamber of Commerce, two months before becoming Cambodia's leader, Prime Minister Hun Manet said the antiquities were national treasures and more than just historical relics.

"They are the blood in our veins and the soul in our hearts that forge the identity of being Khmer... our heritages define who we are and who we will be," he said.

U.S. authorities have spent more than a decade working on locating artifacts from Cambodia and have so far repatriated 65. In 2019, art dealer Douglas Latchford was indicted for wire fraud and other crimes related to selling looted Cambodian artifacts, but the charges were dismissed after his death.