HALIFAX (Reuters) – A massive fire in the eastern Canadian city of Halifax has prompted mandatory evacuation orders for thousands of homes, and officials said residents would not be allowed to return unless they notified municipal authorities.

Halifax Mayor Mike Savage said the evacuations affected about 18,000 people.

Requests released Sunday Covering the Hammonds, Upper Tantallon and Pocock Plains areas. These suburban communities are home to many city workers and are located about 15 miles from Halifax. Surrounded by forests, the residents of the nearby quarters were left restless all night long.

Prime Minister Justin Trudeau in atweetOn Monday he described the bushfire situation in Nova Scotia, where Halifax is located, as “extremely serious” and said his government stood ready to provide any assistance if needed.

Officials said the wildfire also prompted the evacuation of about 400 homes in New Brunswick over the weekend. Mayor of St. Andrews, New Brunswick Brad Henderson said Monday that although progress has been made, the fire remains under control.

Halifax regional deputy chief of fire and emergency Dave Meldrum told reporters Monday morning that the fire was still continuing in the Tantallon and Hammonds Plains area. An investigation into the cause of the fire is still underway, and there have been no reports of any deaths or injuries.

About 100 firefighters battled the blazes overnight, Meldrum said, and he said emergency crews would be working a lot for “many days” to come.

The city declared a local state of emergency late Sunday after a wildfire caused evacuations and power outages, and authorities closed several schools.

The massive fire, aided by strong winds and dry timber, damaged dozens of homes and hampered rescue services. The municipality said the state of emergency will be in effect for seven days, unless it is lifted or extended.

The western Canadian provinces of Alberta and British Columbia also dealt with an unusually warm spring this year that has led to several wildfires burning out of control, slashing oil and gas production. But most of those fires have since been brought under control, helping to restart oil and gas production.

In the major oil-producing province of Alberta, the intensity of one of the most challenging bushfire seasons in years continued to wane, allowing oil and gas producers to cautiously resume production that they had temporarily shut down.

Crescent Point Energy (CPG.TO) said it has restored 45,000 barrels of oil equivalent of production it had previously halted, while Paramount Resources (POU.TO) said it has restored most of the production it had cut due to the fires.

(Reporting by Eric Martin in Halifax and Kanishka Singh in Washington); Additional reporting by Rod Nickell in Winnipeg. Writing by Kanishka Singh; Editing by Andrea Ricci and Leslie Adler

Our standards: Thomson Reuters Trust Principles.