Boston authorities are investigating the circumstances that led to a 9-alarm fire Wednesday that claimed the lives of two city firefighters.
Thirteen other firefighters were injured in the blaze, and several police officers also were taken to hospitals. Some residents had to be rescued from the upper floors of the four-story apartment building in the city's Back Bay area, but none were hurt, city officials said.
"Today's a sad day for the city of Boston," Mayor Marty Walsh said Wednesday. "We lost two heroes here today."
The deceased firefighters were identified as Lt. Edward J. Walsh, a 43-year-old father of three who had almost a decade of experience, and firefighter Michael R. Kennedy, a 33-year-old Marine Corps combat veteran who had been a firefighter for more than six years.
The men were battling fire inside the basement of a brownstone on Beacon Street when a mayday call went out, MyFoxBoston.com reported.
The American flag flew at half-staff outside Engine 33/Ladder 15 on Boylston Street Thursday. A memorial of flowers also grew outside the firehouse where Walsh and Kennedy worked.
"This terrible tragedy reinforces how we must be grateful every single day for the brave men and women who put themselves in danger day in and day out to keep us safe," said Governor Deval Patrick.
New England Patriots quarterback Tom Brady, who lives in the Back Bay, said he extends "deepest sympathies and condolences" to the fire department and families "of our brave and selfless firefighters who gave their lives for our protection and safety today."
Walsh and Kennedy are the first Boston firefighters to die on duty since 2009.
Deputy Fire Chief Joseph Finn said the fire appeared to have started in the basement but moved quickly through the building. The cause wasn't known, but he said all indications are that it was accidental and that it was the wind that caused the fire to spread through the building so quickly. Firewalls stopped the fire from consuming adjacent buildings.
"In 30 years I've never seen a fire travel that fast, escalate that quickly and create such havoc in such a short period of time," Finn said.