Thai police have arrested the head of a child modelling agency after more than 500,000 indecent images of children were found on computer hard drives.
Danudetch "Nene" Saengkaew, 23, has been charged with child sexual abuse and downloading child abuse images.
Investigators say the images were found in a raid on the Nene Modelling Agency, north of the capital Bangkok.
The raid was the culmination of a months-long operation that began with a tip-off from Australian police.
The FBI and New Zealand police were also involved in the investigation, officials said, along with Operation Underground Railroad - a non-profit group that helps governments rescue sex trafficking victims.
According to the Bangkok Post, the Nene agency, in Pathum Thani Province, is one of the best-known child modelling agencies in Thailand.
Thailand's Department of Special Investigation (DSI) said the victims included Thai children and also thousands of others from various countries.
"This is a child-porn industry and we're proud to have cracked it," said Khemachart Prakyhongmanee, a deputy director at DSI, quoted by Channel News Asia (CNA).
He said image files confiscated at the Nene agency had been organised into different folders according to countries. Children's costumes and toys were also seized.
A portfolio found by police during the raid claimed the agency had worked with more than 8,400 child models and actors since 2013, CNA added.
Police Col Korrawat Panprapakorn, director-general of the DSI, told reporters that the raid came a year after Australian authorities contacted them.
An investigation, named Operation Casting Call, was launched but police only had a single photograph of a child to work with, Col Korrawat said.
Painstaking analysis of the image led to the arrest in May last year of a man believed to have taken the picture. He later gave police the address of Nene Modelling Agency, the DSI said.
Col Korrawat said the amount of evidence convinced investigators that the agency "must have been behind the abuse of thousands of children".
Mr Danudetch has been charged with importing pornographic images into a computer system and sexually abusing minors, the Bangkok Post reported.