Massachusetts State Police said it had responded to 70 reports of fires, explosions and the smell of gas in a widespread zone encompassing the east coast towns of Lawrence, Andover and North Andover.

“Gas lines are currently being depressurized,” police tweeted, adding that “it will take some time.”

“Numerous evacuations of neighborhoods where there are gas odors are underway,” police said. “Far too early to speculate on cause. Joint investigation will be conducted when situation is stabilized.”

Authorities were to cut power to thousands of meters, police said, and residents in all three towns with utilities service from Columbia Gas had been asked to evacuate immediately. In a release, the company had said it would “be upgrading natural gas lines in neighborhoods across the state.”

The mayor of Lawrence requested that all those living in the southern zone of his town leave their homes ahead of the planned power shutdown.

Lawrence General Hospital said it was treating 10 patients injured in the gas explosions, one in critical condition and another in serious condition. “Cases range from smoke inhalation to traumatic blast injuries,” the hospital said, adding that one patient had been taken to another hospital.

Red Cross centers were open to shelter evacuees while Lawrence-area schools were to shutter in the upcoming days.

A team of investigators from the National Transportation Safety Board was to head to the scene, the federal agency tweeted.

Massachusetts Governor Charlie Baker said in a statement that he was “actively monitoring the situation,” urging residents to heed the instructions from local officials.