Two 15-year-old girls have been arrested on suspicion of manslaughter after a firefighter was killed tackling a blaze at a city centre hair salon.

Stephen Hunt, 38, was part of a team responding to a fire at Paul's Hair World in Oldham Street, Manchester, when he and a colleague got into difficulties on Saturday night. Colleagues pulled him and another firefighter out of the building. Paramedics treated them at the scene and took them to hospital but Hunt, a firefighter since 2008, was declared dead a few minutes later. His colleague is still being treated in hospital but his injuries are not believed to be life-threatening.

Steve McGuirk, county fire officer for Greater Manchester fire and rescue service, said Hunt had two teenage children and that his family was "absolutely grief-stricken".

"I don't think I have ever seen as much shock and sheer devastation on people's faces," said McGuirk. "The firefighters are clearly devastated by the loss of their colleague and I pay tribute to their professionalism, courage and dedication – while in mourning they are continuing to keep the community safe."

Emergency services were called to the blaze just before 3pm on Saturday. By 3.50pm, 12 crews, comprising more than 60 firefighters, were tackling the blaze. McGuirk said the crews thought they were starting to get it under control by about 8.30pm but for an unknown reason, a "BA emergency" was declared – which is a signal to evacuate the building. It was then that Hunt and his colleague were pulled from the building.

Stephen Hunt, 38, who was declared dead on arrival in hospital after tackling the fire. Photograph: Greater Manchester fire and rescue/PA

"The early indications are an absolutely massive, ferocious and sudden build-up of heat," said McGuirk. "But where that came from and what caused that we have got absolutely no idea at this stage. That's really the purpose of the investigation that we are now engaged in."

Neighbouring fire and rescue services have started an investigation into the incident and circumstances leading to the tragedy alongside Greater Manchester police.

Detective superintendent Phil Owen said: "We are working with our colleagues from the fire service to establish how this fire, which has tragically claimed the life of a firefighter, started. We have already arrested two juveniles in connection with the fire and our inquiries are continuing."Fire Brigades Union general secretary Matt Wrack said the investigation would draw on expertise from around the country. "This is a terrible tragedy, he said. "Firefighters in Greater Manchester and around the UK are devastated by the news. The thoughts of everyone in the fire and rescue service will be Stephen's family, friends and colleagues at this time."

A spokeswoman for Paul's Hair World said: "We are greatly saddened to learn that fireman Stephen Hunt lost his life tackling the blaze at our Manchester shop yesterday.

"Our heartfelt condolences go out to his family and the Greater Manchester fire service at this difficult and sad time." The two 15-year-olds were bailed until September.