HARRISVILLE — Five adults and two children, some wearing only pajamas, fled into freezing temperatures early this morning when fire swept through their apartment building in East Mercer Street, authorities said.

No one was injured but two cats reportedly perished in the fire that started shortly before 2 a.m.

The state police fire marshal is investigating the blaze that appeared to have started in an empty upstairs apartment in back of the two-story wood structure.

The fire gutted the building at 607 E. Mercer St., which once housed a flower shop years ago.

“The fire was through the roof in back when we got there,” said Chief Steve Bickel of the Harrisville Volunteer Fire Department. “We hit it from outside until it was knocked down enough to send (crews) inside.”

All the tenants there at the time were accounted for, fire officials said. None of the occupants appeared to have had time to dress for the cold.

“They mostly got out with whatever clothes they had on at the time,” Bickel said. “No time for coats.”

A Superior Ambulance crew provided blankets for the shivering tenants. The chapter of the American Red Cross was called to assist the victims with emergency needs.

Seven cats were rescued from at least one of the upstairs apartments. Two other cats died.

Authorities said the building, owned by Eric Snyder of Harrisville, included four apartments — one on the first floor and three on the second floor.

All of the apartments were leased.