One person was killed and a number of others were missing after an explosion early on Saturday morning at a block of flats on the island of Jersey, off the coast of northern France.

"Tragically we have one confirmed fatality," Robin Smith, Chief Officer of the States of Jersey Police, said in a video statement. The explosion occurred just before 0400 GMT and the fire has since been extinguished.

Smith confirmed fire services had been called to the property on Friday before the explosion after residents had reported the smell of gas. He did not comment on the cause of the explosion, and said that would be subject to investigation.

Smith said a three-story building, located near the harbour in the island's capital St Helier, had completely collapsed and a search and rescue operation had begun to find around a dozen other people unaccounted for.

He said 20 to 30 people had been evacuated and that there were two "walking wounded" receiving hospital treatment.

Asked about the possibility of more fatalities he said: "There has to be a recognition that we could have more fatalities."

Jersey is a British Crown Dependency with a resident population of just over 100,000 people.

"It's a huge shock to everyone this morning but in the first instance our condolences go to the families who are affected and we're all thinking and praying for those who are worried about their loved ones this morning," said Kristina Moore, Chief Minister of Jersey.