At least four people were killed and several injured in a suspected gas explosion in Taiwan on Thursday, authorities said.

The explosion occurred at the Shin Kong Mitsukoshi department store in the Xitun district of central Taiwan during renovations on the 11th and 12th floors, news channel TVBS World Taiwan reported.

The National Fire Agency, however, said it was "still unclear whether that work was the cause of the incident."

Taichung Mayor Lu Shiow-yen confirmed the fatalities and said six people suffered cardiac arrest and eight were injured. She said two were trapped in an elevator.

Authorities are investigating the accident.