A suspected gas explosion at a department store in Taiwan’s central city of Taichung killed at least four people and injured 26 on Thursday, among them tourists from the gambling hub of Macau, fire officials said.

The blast on the building’s 12th storey, where construction work was taking place, caused damage from the ninth floor upwards, the fire department said in a statement.

Two dead and five injured were tourists from Macau, it added.

The food court of the Taichung Shin Kong Mitsukoshi department store on the 12th floor was closed at the time due to the building work, it added.

One of the injured was in intensive care in hospital, the health ministry said.

Writing on his Facebook page, Taiwan President Lai Ching-te called for a speedy investigation into the cause of the blast.