Canadian police are searching for two suspects in knife attacks that killed 10 people and injured at least 15 others, mostly in a sparsely populated indigenous community, early on Sunday, Reuters reported.

The stabbings, which took place at 13 locations, were among the deadliest mass killings in modern Canadian history and will no doubt reverberate across a country unaccustomed to episodes of mass violence more common in the United States.

“I am shocked and devastated by today’s horrific attacks. As Canadians, we grieve with all those affected by this tragic violence and with the people of Saskatchewan,” Prime Minister Justin Trudeau said in a statement.

Police named the two suspects as Damien Sanderson, 31, and Myles Sanderson, 30, providing photos and descriptions but no other details about their motives or the victims.

In a statement by indigenous leaders, the attacks may have been drug-related.

“This is the devastation we face when harmful illegal drugs invade our communities,” said the Federation of Sovereign Indigenous Nations, which represents Saskatchewan’s 74 First Nations.

“It’s outrageous how prison, drugs and alcohol can destroy so many lives,” Michael Brett Burns told the Aboriginal Television Network.

The suspects were seen hundreds of kilometers away

Police said the two men were traveling in a black Nissan Rogue and were spotted in the town of Regina, about 200 miles (320 km) south of the attacks in the James Smith Cree country and the village of Weldon.

“It appears that some of the victims may have been intentional and others may have been accidental victims. Therefore, it would be extremely difficult to talk about the motives at this time,” Rhonda Blackmore, commander of the Royal Canadian Mounted Police in Saskatchewan, said at a press conference.

There may be other victims who went to different hospitals on their own, the police said.

The James Smith Cree Nation is an indigenous people of approximately 3,400 people who are primarily engaged in agriculture, hunting and fishing. Weldon is a village of about 200 inhabitants.

The nation’s elected elders declared a state of emergency “in response to the multiple killings and attacks on members of the James Smith Cree Nation” and established two operational centers.

Indigenous people make up less than 5% of Canada’s population of approximately 38 million and suffer from higher rates of poverty, unemployment and lower life expectancy than other Canadians.

The first stabbings were reported at 5:40 a.m. on Sunday morning (2:40 p.m. in Romania), and within three hours, police were alerting the entire region about a dangerous person.

In the afternoon, similar alerts were issued in the neighboring provinces of Saskatchewan, Alberta and Manitoba.

Police bulletins urged people to report anyone suspicious and take precautions, including sheltering in place, while warning against hitchhiking or approaching suspicious people.