Around a dozen people are still thought to be missing.

The search for bodies "will take weeks, not days" and will be "meticulous and painstaking", police said.  The emergency services are no longer looking for survivors, Robin Smith, the chief of police, said.

Asked if those who are missing had died, he said: "We've now moved into the recovery phase [of the operation]. So inevitably and tragically and sadly, that is the case."

He said while the search of the debris left after the explosion would not be "quick", it would be both "careful and sensitive".

'Something has gone horribly wrong'

Firefighters, specialist rescue teams and dogs worked through the night to search for survivors in the debris of the building.

Jersey's chief fire officer, Paul Brown, said: "Something clearly has gone wrong because a building has exploded and collapsed. And horribly as well. We're all devastated that Islanders have been lost and that families and loved ones are suffering and will continue to do so."

Family liaison officers are currently working with the families of those affected by the blast, and while authorities say they are in touch with all next of kin, victims are yet to be publicly identified.

'Utter devastation'

The extent of the devastation was evident in video footage posted to Twitter by the Jersey government, which showed piles of rubble, crushed cars and a blown-out window in a neighbouring building.

One person has been killed after an explosion at a block of flats just before 04:00 Saturday morning in St Helier, Jersey off the coast of the United Kingdom.

The police say twelve people are missing and two people were taken to hospital.https://t.co/X1OSSJGdY4

— Nationwide90FM (@NationwideRadio) December 10, 2022

Police described the scene at Haut du Mont on Pier Road as one of "utter devastation".

Around 40 people are being housed in alternative accommodation following the blast, which happened at around 04:00 on Saturday.

'Too early to speculate' about cause

The fire service was called to the building at around 20:30 on Friday, hours before the blast, after residents reported smelling gas.

When asked what could cause such a "ferocious" explosion, Paul Brown, the chief fire officer, said there were "many different potential causes", but it was too early to speculate.

Residents who lived in the flats have been moved to St Helier Town Hall, where they continue to be supported.

Sky News