Family members say Laura Macintyre and Eilidh MacLeod haven't been heard from since the explosion.
Two Rescued From Edinburgh Fire
Two people have been rescued by fire crews after a major blaze left them trapped in a block of flats.
The pair were taken to hospital as around 50 firefighters battled the flames.
The Scottish Fire and Rescue Service received several 999 calls to the property in Edinburgh's Lower Granton Road shortly before 7.15pm on Wednesday.
They were confronted with a "severe fire'' in a ground floor flat which was spreading to floors above.
Staff at the operations control centre gave survival guidance to those who were unable to leave their homes and directed frontline crews to them.
Search and rescue teams using breathing equipment fought their way through choking smoke to bring two people out of the building, SFRS said.
Both were taken to Edinburgh Royal Infirmary by ambulance.
Other firefighters fought the blaze from inside the building and from a turntable ladder outside.
Crews remained at the scene overnight to dampen down and check for any hidden fire spread.
A spokesman said: "Around 50 firefighters were involved at the height of the incident, with 11 fire engines sent to the scene.
"Specialist officers from the SFRS Fire Investigation Unit have also attended and will work to establish the circumstances surrounding the incident.''
The families of two girls from the Western Isles missing after attending the concert in Manchester targeted in a terror attack have issued appeals on social media.
Crews were called to the former Royal Victoria Hospital site this afternoon.
John Bermingham was also accused of assault and a breach of a Sexual Offences Prevention Order.
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