A father and several of his children are feared to have died in a fire at a remote farmhouse in Powys.
Three children, aged 10, 12 and 13, escaped the blaze near Llangammarch Wells just after midnight on Monday and are being treated in hospital.
One of the people unaccounted for has been named locally as David Cuthbertson who is believed to be in his sixties.
Police confirmed people were missing and some had died in the fire, adding the cause of the blaze was unexplained.
Local Conservative MP Chris Davies said: “I am absolutely devastated at today’s news that there was an overnight fire in Llangammarch Wells, which has claimed the lives of a father and his young children.
“As a father to two young girls, this news has shocked me to the core. My thoughts are with the family and local community at this terrible time.”
Ron Birchall, 73, who lives at the former Aberceiros Inn in the village, described Mr Cuthbertson as “a great guy”.
He added: “All I can say is that he was a great father who loved his kids and doted on them.
“I used to see him walking around the village or in his vehicle. We saw the kids coming to pick up the bus to school.”
A joint police and fire service statement said the children who escaped had non life-threatening injuries.
It continued: “Due to the severity of damage at the scene we are unable at this stage to identify any of the deceased or confirm numbers.
“Specialist scientists and fire investigators are still assessing the scene prior to further investigation.”
Mid and West Wales Fire and Rescue Service said its crews were faced with an “extremely difficult situation” at the scene and firefighters did all they could to handle the situation.
A spokesman added: “Our deepest sympathies go out to the family and the residents of Llangammarch Wells following this tragic incident.”
Ch Insp Martin Slevin, of Dyfed-Powys Police, told a press conference the investigation into the fire and the recovery of the victims’ bodies would be difficult.
He described the scene as “chaotic” with “significant” damage to the structure of the building, but said officers would work to provide answers about the cause of the blaze.
Powys councillor Tim Van-Rees, who represents the Llanwrtyd Wells area and who knew the family who lived at the property, described the incident as “devastating”.
He said: “It is absolutely shocking and a devastating blow and it is possibly just as well we are in half-term at the moment because the effect on our children and the schools would have been very severe.
“I have spoken to the owner of the property who was alerted and telephoned the fire brigade and I must say as a member of the fire authority the local fire brigade were outstanding.”
He said firefighters “risked life and limb” to see whether anything could be done but “unfortunately their efforts were not well rewarded”.
He added: “Speaking on behalf of the community our thoughts and prayers will all those affected. The community will come together and do all it can for the surviving children and relations.”
Brecon and Radnorshire AM Kirsty Williams tweeted: “Tragic, devastating news for the community. My deepest sympathies to those affected.”
A number of ambulances were sent to the house, while 20 members of Brecon Mountain Rescue Team helped search the surrounding area for casualties.
Llangammarch Wells is the smallest of the four spa villages and towns of mid Wales, the others being Llandrindod Wells, Builth Wells and Llanwrtyd Wells.
It lies on the River Irfon and has a population of just under 500 people.