At least four people have been killed and two others are critically injured in a mass shooting after a male gunman opened fire at a school in western Canada. The incident happened at the community school in La Loche, 600 kilometres (375 miles) from Saskatoon in the province of Saskatchewan.

Prime Minister Justin Trudeau said that the gunman who carried out the mass shooting is in custody and the situation is currently under control. He was in Davos, Switzerland, for the annual World Economic Forum. According to Reuters, Trudeau called the attack as “every parent’s nightmare.”

“When I spoke with community leaders they obviously expressed that the community is reeling,” he said in a televised address. “The country’s heart is breaking for the people of La Loche, Saskatchewan today.”

La Loche’s acting Mayor Kevin Janvier told the Canadian Press that he is not “100 per cent sure what’s actually happened but it started at home and ended at the school.”

Noel Desjarlais, La Loche Grade 10 student and eye witness told the CBC (via Sky News) that he ran outside the school after hearing multiple gunshots.

“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,” Desjarlais is quoted as saying by the website.

The school also posted about the situation on its Facebook page, writing that it was “under lockdown.” “There is currently an emergency occurring at the Dene Building and we are asking the public to stay away while the matter is resolved by the Royal Canadian Mounted Police (RCMP),” the school wrote about the mass shooting.

“The elementary school is also under a lock down which will not be lifted until we hear that it is safe from the La Loche RCMP. We will not be allowing anyone in or out until we have a clear idea of what is going on,” it added.

Canadian Premier Brad Wall also issued a statement about the mass shooting saying that he was shocked beyond words because of “the horrific events today in La Loche.”

“My thoughts and prayers are with all the victims, their families and friends and all the people of the community,” he added.

The incident is shocking as mass shooting is not very common in Canada. The country has stricter gun laws than the United States.

Update: New reports are suggesting that four (not five as reported earlier) people were killed in the tragic mass shooting. Janvier told The Associated Press that his 23-year old daughter Marie, a teacher, was shot dead by the alleged gunman. The gunman allegedly shot two of his siblings first before killing Janvier’s daughter. It is not know if the alleged shooter knew Janvier’s daughter.