A fire that killed 22 people and injured three in Liaoyang of Liaoning province was neither caused by arson nor a gas explosion, authorities announced at a Wednesday news briefing.

The blaze broke out on Tuesday at a restaurant located near a residential relocation building in the Baita district of Liaoyang city.

By 2 pm that day, the fire had claimed the lives of 22 people and left three others injured.

Guo Yunfeng, mayor of Liaoyang, said that investigations indicated that the fire started near the entrance of the establishment. Authorities found no gas pipelines inside the restaurant, and three gas cylinders located on-site remained intact.

READ MORE: Xi urges all-out efforts to treat the injured in restaurant fire in Liaoning province

As a result, both arson and a gas explosion have been ruled out, although the exact cause of the fire remains under investigation.

The rapid spread of the fire was fueled by flammable furniture and interior materials, combined with strong outdoor winds.

This quickly blocked the exits, trapping people inside. Many victims succumbed to suffocation from toxic fumes within a short period, said Guo.

Police have cordoned off the area and detained the restaurant's operator for further investigation.

Zhang Tongtong contributed to this story.