At least 25 people were killed and 267 injured when underground gas explosions ripped through Taiwan’s second-largest city, Kaohsiung, on Thursday night and early yesterday.

The series of blasts hurled concrete and cars through the air and blasted long trenches in the streets, rescue authorities said.

The series of five explosions struck a densely populated district where petrochemical companies operate pipelines alongside the sewer system.

Firefighters called to investigate a gas leak were among the victims when the blasts went off hours later, upending at least six fire appliances.

Four firefighters were among the 25 dead. Some 267 people were injured, the National Fire Agency said.

The blasts were believed to be caused by a leak of propene but the cause and source of the leak were not immediately clear, officials said.

The exploded gas line belongs to the government-owned CPC fuel company, which claimed no problems were apparent before the explosions.