Nicole Daniels holds a picture of her son, Evander. The 22-month-old child drowned while in foster care last week. (David Shield/CBC)

Thirteen Saskatchewan children involved in Saskatchewan's child-welfare system have died between Jan. 1 and June 1 of 2010, the government said on Monday.

But Social Services Minister Donna Harpauer is blaming many of the deaths on pre-existing medical conditions.

"Many of the children that come into the care of the ministry … have very extensive — many of them have very extensive medical challenges," Harpauer said, in her first interview with CBC News since the death of a foster child last week.

The ministry has been under fire since Evander Daniels drowned in a bathtub in his foster home near Aberdeen, Sask. on Tuesday. An autopsy report also said that scald-type burns may have contributed to his death.

Between 15 and 20 children in care die in the province each year — many of the deaths go unreported to the public, yet each of them is a tragedy, Harpauer said.

"There is no child death that isn't a tragedy. Can I prevent health challenges in these children? No I can't," she said.

"What I can do is the best I can do for the safety of children."

First Nations groups, however, are critical of Harpauer's message and are calling for a public inquiry into Daniels's death. Aberdeen is about 40 kilometres northeast of Saskatoon.

While RCMP and social services continue to investigate what happened, officials on his home reserve of Sturgeon Lake First Nation said Daniels is the second foster child from the reserve to die in the last six months.

Harpauer said she won't call an inquiry until she hears back from investigators.

"In this particular case … I think there is an assumption that I know more than I know yet," she said.

"I am waiting on the same reports everyone else is."