A massive explosion ‌at ‌a fireworks factory has ⁠killed 21 ​people and injured 61 others in a Chinese city touted as the world’s largest producer of fireworks.

People within a three-kilometre radius were forced to evacuate amid fears there could be secondary blasts due to nearby black powder warehouses.

The explosion occurred in ‌the city ​of Liuyang, Changsha, on ​Monday afternoon, ​local time.

Residents reported that the intensity impacted their homes.

“The glass windows in our homes were shattered, aluminium window frames were deformed, and even the stainless-steel doors were twisted out of shape,” a resident said, according to the BBC.

Drone video shows what looks to be several buildings completely wiped out as thick smoke lingers over the blast site.

Almost 500 rescuers were deployed to the scene and evacuations were conducted in danger zones.

The factory was blown to smithereens. Photo: BBC video screenshot

Liuyang touts itself as the ‘birthplace of fireworks’ dating back around 1400 years.

With more than 3000 fireworks factories today, it claims to be the world’s largest producer of fireworks — producing more than half of the world’s fireworks.

China’s President ‌Xi Jinping ‌called for a thorough ​investigation, state media reported on Tuesday.

Xi also ​ordered authorities to strengthen risk screening and hazard ​control ​in ​key industries, enhance ‌public safety management and ensure the safety of people’s lives and property, according to ​the Xinhua news agency.

-with APP/AP