An explosion on Monday in a fireworks factory in southern China killed at least 21 people and injured dozens more, prompting the nation’s leader, Xi Jinping, to demand a rapid investigation and punishment for those responsible.

The explosion erupted in a factory in Liuyang, Hunan Province, on Monday afternoon, but the scale of destruction only started to become clear a day later. Video from the aftermath showed rescuers with searchlights looking through smoldering rubble and shattered windows of homes some 300 yards from the explosion.

The Chinese government often holds back details of accidents while it gathers information and prepares to issue a response. But the explosion appears to be one of China’s deadliest in recent years. In a sign of its seriousness, Mr. Xi on Tuesday urged investigators to identify and hold accountable those responsible and “strengthen identification and correction of risks and hazards in key industries,” according to People’s Daily, the official newspaper of the Chinese Communist Party.

The number of dead could still rise. Officials said on Tuesday that 61 people were injured by the blast, but did not describe the extent of the injuries or how many dead or wounded were factory workers or nearby residents. A report from China’s state broadcaster, CCTV, said many of the injuries were broken limbs.

China has long been plagued by deadly industrial accidents. In 2019, an explosion at a chemical plant in the east killed 78 people. In the past decade, the government has tightened safety controls, reducing the number of industrial explosions and mine disasters. Last year, over 18,000 people died in workplace accidents in China, a 7 percent decline since 2024, according to the Ministry of Emergency Management.

But factories that make fireworks remain a vulnerability. In 2019, another fireworks factory explosion in Liuyang killed 13 people. Officials had initially claimed that only seven people died, concealing the extent of the accident, investigators later found.

Liuyang has long been a center for making fireworks, which are lit during many festivals and celebrations. The industry sustains tens of thousands of jobs there, according to a 2023 report from Xinhua, the official Chinese news agency.

Emergency workers at the site of the latest accident remained worried about further blasts at the shattered factory, and said two explosive powder warehouses were “high-risk,” Xinhua reported.

Amy Chang Chien contributed reporting from Taipei, Taiwan.