(ECNS) -- Seven people were killed and 27 others injured in an explosion in north China's Hebei Province on Wednesday, local authorities said Thursday. 

The blast, suspected to have been triggered by a gas leak, occurred at 7:54 a.m. Wednesday in a food shop in Yanjiao town of Sanhe city, an area under the administration of Langfang, Hebei Province, according to the city's emergency management bureau.

Li Xiujuan (pseudonym) and her grandson were among the injured.

Li and her grandson were walking up the stairs when the explosion happened. They were trapped in the stairwell of the building in the debris.

She recalled that the Tai Chi team she attended postponed their practice due to a member's absence, or they might have been severely injured in the accident, according to Jiemian News.

After the explosion, rescuers helped them escape. Li's grandson lost one of his shoes and one rescuer immediately took off one of his boots and put it on him He treaded barefoot on the glass shards in the debris.

Li handed over a mat and a rope, asking the rescuer to protect his feet, Jiemian News reported.

Li recalled that when the explosion occurred, the shop on the first floor hadn't opened yet, and there were few customers. The dance studio on the third and fourth floors also had no one present, except for an elderly lady who was on duty and often stayed there. During the incident, she fell from the building and was later diagnosed with a minor concussion at a local hospital.

She was concerned about a teammate named Qin Li. According to Li's speculation, Qin was walking in the stairwell on the first floor when the explosion occurred.

Following the accident, both Li and Qin's family were unable to reach her via phone.

According to Jiemian News, across the intersection from the exploded building was an elementary school. As most children typically begin their school day around 7:30 a.m., by the time of the explosion, the majority of children had entered the campus.

Among the 27 injured, 14 have been discharged from the hospital, and the remaining are not in life-threatening condition.

An investigation is still ongoing.