A United States grand jury has indicted the alleged operator of a massive child pornography website, as law enforcement officials arrested hundreds more in a global crackdown.

More than 300 arrested and charged

Justice Department prosecutors said in a statement today that a 23-year-old South Korean man, Jong Woo Son, was indicted for running Welcome To Video, which officials described as the largest market for child exploitation by “volume of content.” In the statement, prosecutors said more than 300 other people across the United States and the world have also been arrested and charged for allegedly using the site.

In a nine-count indictment, prosecutors said Son was arrested in March of last year, and the server used to operate Welcome to Video was seized. According to the indictment, law enforcement from multiple countries uncovered eight terabytes of video, 45 percent of which contained footage of child exploitation not previously known to exist.

The website, according to the indictment, sold videos to users through bitcoin transactions, which investigators were able to tie to users of the site. Son has been convicted in South Korea and is currently serving his sentence in the country.

“Children around the world are safer because of the actions taken by US and foreign law enforcement to prosecute this case and recover funds for victims,” US Attorney Jessie K. Liu said in a statement announcing the bust. “We will continue to pursue such criminals on and off the darknet in the United States and abroad, to ensure they receive the punishment their terrible crimes deserve.”