Belgium’s French-language broadcaster RTBF reported that a gas leak was suspected as the cause of the blast at around 9.30pm local time on Monday, though it had yet to be confirmed.

Police said in a statement that 14 people were taken to hospitals, including one in critical condition and five in a serious condition.

They said emergency services pulled several people from the debris of the buildings in the Paardenmarkt area of central Antwerp, a Dutch-speaking northern city, but could not rule out finding others as searches continued.

Police said the explosion was not related to terrorism. Belgium has been on a high state of alert since 16 people were killed in suicide bombings in Brussels in March 2016.

Several buildings either collapsed or were badly damaged in the blast, police said.