People on the Opaskwayak Cree Nation are shocked and horrified after a fire killed two children on the Manitoba reserve Tuesday afternoon.

The children were trapped in a wooden garden shed that caught fire. By the time firefighters arrived, the shed was engulfed in flames.

The wooden shed sat on the lot of a home that burned down a few weeks ago, and was being used to store tools and propane tanks, Capt. Louis Personius of the OCN Fire Department told CBC News.

He found their bodies once the fire was extinguished.

"I first searched and I noticed a body in the corner of a building and I knew that right away," he said. "I told RCMP I found one, then I continued in my search and I found another one. They were pretty close together."

The shed, located near a playground, was locked, but the children may have crawled in a hole in the back of the shed, then couldn't get back out when the fire started, Personius said.

The identities of the children will be determined by autopsy, but Personius says they counted the children in the community and two young cousins are missing.

"It's hard right now, hard for everybody," he said.

Counsellors are on hand to talk to the family and to other children who witnessed the blaze, he said.

"My nephews and that came running in," he said. "They heard the kids screaming, and they seen the fire coming out."

RCMP and the provincial fire commissioner's office are investigating. Foul play has been ruled out.