LONDON (AP) — The number of people killed in an apartment building explosion and fire on the English Channel Island of Jersey has risen to five, and four others are still unaccounted for, police said Sunday.

Robin Smith, chief of Jersey Police, said specialist teams were continuing a painstaking search of the area in St Helier, the island’s capital, and warned it was likely to be weeks before investigations are completed.

“There are still a number of residents, we are working on the assumption of four, that remain unaccounted for,” he said. “Their families were made aware of this announcement before other islanders. They continue to be supported by special officers.”

A blast destroyed a three-story apartment block in St. Helier at about 4:00 am on Saturday. Smith said the fire was “likely” caused by a gas explosion, but that has not yet been confirmed.

Smith said the fire service had been called to the area the night before after residents reported smelling gas. He said police would investigate “whether or not there was a safety issue” with natural gas lines.

Authorities said Sunday that the search mission was now a “recovery operation” and they no longer expect to find anyone alive.

“We have moved to a recovery stage, it’s a moment to think about the families,” Smith said.

Jersey, the largest of the Channel Islands, is a self-governing dependency of the United Kingdom located off the coast of northern France in the English Channel.

Gas supplier Island Energy said it is working with the fire service to “understand exactly what has happened.”