Beijing. A fire broke out at a shoe factory in the eastern Chinese province of Fujian on Thursday, killing 28 people, the official Xinhua News Agency said.

Chinese President Xi Jinping on Thursday demanded “an all-out search and rescue effort." He urged swift investigation of the incident and “strictly hold those responsible accountable.”

The blaze started at a factory by the Huiteng shoe company in the city of Jinjiang, also known as China’s shoe capital, the city’s fire department said in a statement. The cause of the fire was not immediately known, and it was unclear whether more people were injured in one of the deadliest fires in China in recent years. Local media reports said people had been trapped on the rooftop.

Xinhua said the factory’s owner and others in charge have been taken into custody and the company’s accounts have been frozen.

Video by the state broadcaster CCTV shows the facade of a building of several floors charred black and covered in white smoke. Earlier footage shows fires were burning on multiple floors, and the building was shrouded in thick, black smoke.