A group of young people were seen running from the building shortly after the fire started at 4pm on Thursday.
“I can confirm that two young people handed themselves in at two separate police stations in the late hours of last night,” Acting Assistant Commissioner Paul Dunstan said today.
“We are speaking with these young people throughout the evening and they are now assisting police with our inquiries.
He said one of the 13-year-olds handed themselves into Paddington Police Station and the other went to Kings Cross Station.
The teenagers were not known to police,” Dunstan said.
“I can further confirm we are aware of a further three or four other young people who were present during the fire,” he added.
Dunstan said police have asked them to come forward with their parents.
The building had been vacant for about 12 months while deconstruction work was taking place.
“We are aware that some people from time to time sleep rough at that location and young people visiting is not something we are aware of prior to yesterday,” Dunstan said.
Police are working with homelessness agencies to locate those people.
Thirteen people have been located and they are working to find two others.
Dunstan described the inferno as a “once in decade type of fire”.
He said firefighters did an “exceptional” job at working quickly to stop the spread and to get people out of danger, especially those on nearby rooftops, balconies and below on the street before the wall crumbled.
There was a mix of new and experienced firefighters who attended the scene.
“If it had not been for the good action there, we could have easily had numbers of firefighters killed or seriously injured so I am very proud and very grateful for the wonderful work they did,” Dunstan said.
“We have a building that is well over 100-years-old, we have all the dry timber that is in that.
“It is all stacked up on the framework, the building, the floors, staircases and so forth.
“Enabling the fire to spread quickly vertically and that is what we saw.
“It was the perfect set of conditions for an intense fire.”
The charred remains of the buildings in Surry Hills are still at risk of imminent collapse and could hurl tonnes of bricks onto the streets below, with closures remaining in place for safety reasons.
Residents still evacuated
The fire continued to burn throughout the night and it would take some time for it to be completely extinguished, Fire and Rescue NSW Acting Commissioner Jeremy Fewtrell said.
“It is quite challenging to extinguish the remaining pockets of the fire because of all the collapsed debris that have fallen down but we continue to just keep wetting down the hotspots.”
He said fire crews were working with Engineers from NSW Public Works to asses the “risk of the remaining walls”.
Depending on the risk, the walls could be “knocked down in a safe way”.
The building on 38 Chalmers Street and a building on Randle Street will remain evacuated for seven days.
Buildings on 1-5 Randle Street remain without power.
“Discussion are taking place with Energy Australia to make an alternative connection,” Fewtrell said.
He said they were aware of the impact the fire had on residents and encouraged them to contact Red Cross for support.
Diversions are still in place around the buildings.
Fire crews save wedding dress
Firefighters managed to retrieve a wedding dress for a woman, from one of the evacuated buildings, as she was about to get married in Tasmania.
“That is a happy bride, I would imagine,” Dunstan said.
Crews also went back into building to get medication and pets for the displaced residents.
Images emerged of firefighters carrying dogs to safety away from the flames.
Drones have been sent in and NSW Police arson squad is taking charge of the investigation.
Photos from the top of a nearby building show how far the debris from the falling walls spread in the area, covering the surface of Randle St.
Neighbouring blocks of offices and apartments were also damaged.
Earlier, Fire and Rescue NSW Superintendent Adam Dewberry said the blaze was finally “pretty much out” with the last of the hotspots quenched by 2am.
But there remained a “very good chance” further walls could collapse.
“We are talking about tonnes and tonnes of bricks that could come down and become projectiles,” Dewberry told Today.
“That is why we have such a tight exclusion zone, not allowing anyone in, including firefighters, until we get the engineers in.”
Dewberry said the priority was getting people back into their homes and offices, but he warned there was a lot of work to be done.
On Thursday, hundreds of people were evacuated from the area as the fire burned through several levels near Central Station.
Authorities said it was “incredibly lucky” no firefighters were killed, though one suffered a minor arm burn.
More than 100 firefighters were called to the scene from multiple stations across Sydney, needing hours to contain the blaze with a combination of aerial and ground attacks.