Dozens of federal agents searched the Los Angeles County Museum of Art, Pasadena's Pacific Asia Museum, the Bowers Museum in Santa Ana and Mingei International Museum in San Diego Thursday, the Los Angeles Times reported.

According to search warrants, they were looking for objects and records pertaining to items allegedly looted from Thailand, Myanmar, China and Native American sites within the United States.

The warrants empowered the agents to search the museums' galleries, offices, storage areas and computer archives.

The raids stemmed from an investigation of alleged art smuggler Robert Olson and the owner of a Los Angeles Asian art gallery, Jonathan Markell, the Times said.

Museum officials defended their acquisition practices to the newspaper and said they plan to cooperate fully in the investigations.

No arrests were made.