The Northwest Territories is mandating masks, banning gatherings and closing non-essential businesses in two communities where COVID-19 cases have been identified.

There was one confirmed case and 15 probable cases Monday in Fort Good Hope, a community of about 600 people. Colville Lake, where about 150 people live, had two confirmed cases. Another probable case was in Deline on the shore of Great Bear Lake. The communities are all in the Sahtu region of the territory's northwest.

There were also four probable infections farther south in Yellowknife.

The 23 cases are "connected to travel or residence" in Fort Good Hope and Colville Lake, chief public health officer Dr. Kami Kandola said.

She said a hand games event that ran from Aug. 5 to Aug. 9 in Fort Good Hope is considered a "super-spreader event" that contributed to the cases.

Health Minister Julie Green said although the territory has dealt with outbreaks in the past, the N.W. T. is now at "a critical moment."

"It's quickly becoming a multi-community event and will likely place tremendous strain on our health system's resources," Green said. "This is a serious situation."

Fort Good Hope and Colville Lake are under a 10-day lockdown with specific rules for vaccinated and unvaccinated residents.

Unvaccinated people who were in either community on or after Aug. 5 must isolate for 10 days and get a COVID-19 test. Vaccinated people need to monitor for symptoms.

'A serious situation': COVID-19 cases force two #NWT communities into #lockdown. #COVID19

Kandola said there is a "high risk of a regional outbreak" connected to culture and travel in the region. "At this time, we are in testing and containment mode to stem further transmission."

Rapid response teams are on the ground and all residents in the affected communities are asked to follow public health orders.

"Because of the close connections, we consider everyone in Fort Good Hope and Colville Lake [as] exposed to COVID-19," Kandola said.

Although everyone exposed is at risk of developing COVID-19, unvaccinated people face a much higher risk, she added. She urged those who have not been immunized to get a shot immediately.

The cases are the first in the territory since an outbreak at a Yellowknife school in June.

This report by The Canadian Press was first published Aug. 16, 2021.

— By Emma Tranter in Iqaluit

This story was produced with the financial assistance of the Facebook-Canadian Press News Fellowship.