At least three people have died after an explosion in a block of flats in Jersey.

About a dozen people are missing in St Helier and there are two “walking wounded” being treated at the hospital, officials say.

The deaths came at around 4am on Saturday after a huge blast which caused the three-storey building in St Helier to collapse.

Chief Minister Kristina Moore announced that at least three people had died, with a search and rescue operation for further people ongoing.

She said it was an “unimaginable tragedy” for the Channel Island.

Chief of States of Jersey Police Robin Smith added: “This is a protracted incident and this is going to go on for days, maybe weeks, and therefore it is important to have resources to continue to keep going.”

He said he expected the search and rescue effort to take “a number of days”.

Mr Smith said the force received reports of a “large explosion” at roughly 4am on Saturday at a block of flats in Pier Road, St Helier.

He said: “We have a three-storey building that has completely collapsed – described from a demolition point of view as a pancake that has dropped almost straight down.

“There is also damage to a nearby building as well, another block of flats that the fire service needs to make safe. It is a pretty devastating scene, I regret to say.”

He said Jersey Fire and Rescue Service were liaising with Hampshire Fire and Rescue to help with the search.

Mr Smith added between 20 and 30 people evacuated from the area had been taken to St Helier Town Hall.

The force said in a statement: “Following the explosion this morning at Haut du Mont, Pier Road, a number of residents are still missing.

“Emergency services are working at the scene and have commenced a surface search of the site.

“Relatives are being contacted by Family Liaison Officers.”

The force said the fire has been extinguished, but emergency services are still “carrying out significant work” at the scene, which is cordoned off, and people have been asked to avoid the area.

Chief minister of Jersey, Kristina Moore, said the flats were run by Andium Homes who were working to ensure anyone who has been displaced has somewhere to stay on Saturday night.

She also paid tribute to the emergency services for their ongoing work at the scene, which she said would take “some days” to clear.

Speaking at a press conference on Saturday morning, Ms Moore said: “Through these difficult times, I think it’s reassuring for everyone to see what amazing strength we have within our emergency services and, again, we just thank everybody who stepped up and came to the rescue and continue to work on the scene.

“This is going to take some days and we will keep everyone updated and fully informed and we will do our very best to ensure everybody is properly looked after.”

Asked how many people were still missing, Mr Smith said: “Given the destruction of the building it is hard to properly assess the numbers.

“We are looking in the region of around a dozen currently, but you will appreciate also that number could fluctuate.”

Daniel Hunt, 19, who lives across the bay, told the PA news agency the explosion woke him at around 4am.

“My bedroom was shaken from the explosion with the windows rattling, which was all very unnerving,” he said.

“I went outside to take a look… I could see what looked like police and firefighters shining torches through windows of surrounding buildings. I assume as they were evacuating the surrounding area.

“The building (was) up in flames with smoke pouring out of the windows.

“To have this happen so close and so early in the morning you don’t know what to think.”