One person died in a three-alarm fire Saturday night at the apartment building at 17 Fifth Ave., Pelham Fire Chief Robert Benkwitt told WNBC.

The Pelham Fire Department was dispatched at about 8:09 p.m. and “met with heavy fire coming out of the window,” said Benkwitt in the interview.

There was one fatality, with the cause under investigation, he said. Benkwitt told WNBC the fire started on the fourth floor of the building. The cause is unknown.

As the fire was being fought, multiple emergency vehicles crowded Fifth Avenue, closing off traffic flow in the First Street and Fifth Avenue intersection. Engines from numerous departments, police and other emergency services lined the avenue.

Residents watched smoke pour out of the windows from the park across the street, to which they had been evacuated, many in pajamas and coats.

Mutual aid arrived from Eastchester, New Rochelle, Mount Vernon, Greenville, Fairview, Larchmont, Scarsdale and White Plains, according to Benkwitt.

“The American Red Cross has been working with building management to help displaced residents and those in need of assistance with food, supplies, counseling, etc.,” said a Village of Pelham Nixle alert sent out at 12:32 p.m. on Sunday.

According to the alert, some tenants have been able to reenter their apartments, and the Town of Pelham provided temporary shelter at the Daronco Townhouse for residents in need.