A grizzly bear is believed to have attacked and killed two people at a national park in southwest Canada, park officials said on Sunday.

Parks Canada said it learned of the attack via an alert sent around 8 p.m. on Friday from a satellite device inside Banff National Park in Alberta, Canada, according to a statement shared on the park’s Facebook page.

GPS coordinates showed the alert was sent from west of Ya Ha Tinda Ranch in the Red Deer River Valley, around 80 miles northwest of Calgary, Alberta. Bad weather hindered a response team from reaching the site by helicopter, so they instead traveled by ground overnight, officials said.

The team, which specialized in responding to wildlife attacks, arrived at 1 a.m. on Saturday to find the two dead people, as well as a grizzly bear that was displaying “aggressive behavior.” They euthanized the bear on-site “to ensure public safety,” according to the statement. The police arrived at 5 a.m. and helped transport the victims to Sundre, a town about 40 miles east.

The victims have not been named, but the CBC reported that they were a married couple. Kim Titchener, who lives in Edmonton, near Banff National Park, and who is a friend of a close relative of the couple, said their dog had also been killed in the attack. “They were in a very remote area,” Ms. Titchener, a wildlife conflict specialist, said in a phone interview on Sunday.

Parks Canada did not immediately respond to requests for further information about the victims or the attack.

An estimated 691 grizzly bears live in Alberta, 65 of them in Banff National Park, according to Parks Canada, which reminds visitors to be prepared for encounters. It advises traveling in groups, making noise and carrying bear spray. In Alberta, the grizzly bear, a largely solitary, omnivorous animal that can live as long as 30 years in the wild, is listed as “threatened.”

Bear attacks on humans are relatively rare, but they can occur when a bear is feeding, protecting its young or surprised. Attacks that kill more than one person appear to be even rarer.

In January, a polar bear killed a 24-year-old mother and her 1-year-old son in Wales, Alaska. In 2018, a grizzly bear, which the authorities later described as starving, killed a woman and her baby in Yukon, Canada.

Banff National Park described Friday’s attack as a “tragic incident” and expressed its condolences to the families and friends of the victims. As a safety precaution, park authorities closed the Red Deer and Panther valleys until further notice.