Canada Saskatchewan high school shooting
The Dene high school campus of the La Loche Community School is seen in an undated photo. Five people were killed and two critically injured in a school shooting in a remote part of Saskatchewan on January 22, 2016 Reuters

Four people were killed and an 'unknown; number were injured in a school shooting in a remote part of Saskatchewan in Canada on Friday.

The worst shooting incident in Canada in a decade happened in the Dene Building high school and another location in Saskatchewan, Reuters reported, citing Canadian police.

The location of the incident, La Loche, is about 600 km north of the city of Saskatoon.

"The country's heart is breaking for the people of La Loche, Saskatchewan today... Obviously this is every parent's worst nightmare," Prime Minister Justin Trudeau said in Davos, Switzerland, where he is taking part in the World Economic Forum.

Canadian police said a male suspect has been taken into custody outside the school and gun was seized.

Police have not ascertained a motive behind the shooting and details of the incident remained sketchy. A mobile video footage telecast on Canadian Broadcasting Corporation showed students walking away from the school even as emergency personnel were moving in, Reuters reported.

La Loche Community School for kindergarten through to grade 12 teaches around 900 students, BBC reported.

"I ran outside the school ... There was lots of screaming, there was about six, seven shots before I got outside. I believe there was more shots by the time I did get out," Noel Desjarlais, a Grade 10 student and eyewitness, told BBC.