The blast and a subsequent fire occurred on Saturday in a three-story building in the town of St. Helier. British media reported on Saturday that at least three people were killed by the blast, while ten others were missing.
"The number of Islanders confirmed to have been killed in the blast is now 5. There are a number of residents, we're working on the assumption of 4, that are unaccounted for," States of Jersey Police said on Twitter on Sunday.
According to the chief officer of the States of Jersey Police, Robin Smith, residents had reported smelling gas the night before the explosion.
The exact cause of the blast is still under investigation.