The RCMP say a cross-country child pornography investigation has resulted in the arrest of 21 people in the Prairies, Nunavut and the N.W.T.

So far, charges have been laid against 16 of those arrested, police told reporters on Wednesday at a press conference in Regina

The charges include sexual assault, invitation to sexual touching, and distributing and possessing child pornography. Police said more charges are pending.

Police hold a news conference in Regina to release details of a joint child pornography investigation that has led to 21 arrests in several provinces and territories. (CBC)

Saskatoon Det. Sgt. Darren Parisien, who led the operation for the Canadian Police Centre for Missing and Exploited Children, said hundreds of thousands of images have been found on more than 100 computers and 1,000 discs.

Parisien said most of the children in the images were under the age of 12, including a number of infants and toddlers.

"More and more increasingly we're dealing with images of infants, toddlers, and children who can't even speak," he said.

Police said a Saskatoon youth had been rescued during the investigations.

According to police, the boy was abused by a family member's roommate. The abuse started five years ago, when the boy was about eight or nine years old, and ended when police executed a search warrant last June.

One person has been convicted in that case and is currently serving a prison term in Prince Albert, Sask.

Operation Snapshot was launched in June and involves 14 different police units in 15 communities.

"A lot of the child sexual abuse material is being produced through the victimization of children right here in Canada and certainly North America," Parisien said. "This isn't a problem where it's coming from other locations."

The arrests announced Wednesday were not the result of a child pornography ring, police said. Instead the criminal cases are largely independent of one another.

Expert sees growing problem

Karyn Kennedy, the executive director of anti-child abuse agency Boost, said that such investigations often uncover children who are being victimized in many other countries.

Investigators have to review all of the evidence they have collected — sometimes hundreds of thousands of images — and relay what they find to investigators around the globe, Kennedy told CBC News.

Making and trafficking child pornography online has become disturbingly common, she said, but a lack of resources means there are relatively few arrests considering the scale of the problem.

"It's happening in small towns, it's happening in large cities, it's happening throughout North America and the rest of the world," Kennedy said.

"It's just resources that keep them from making more and more of these arrests."