All-out rescue efforts continued on Sunday to locate two people still unaccounted for after a deadly coal mine accident in Shanxi province.

A gas explosion struck the Liushenyu coal mine in Qinyuan county of the city of Changzhi at 7:29 pm on Friday. A total of 82 people were confirmed dead, and two were missing.

A total of 128 people were injured and were receiving hospital treatment, including two in critical condition and two in serious condition. Another 35 people without serious injuries returned home.

President Xi Jinping, who is also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission, has urged all-out efforts to rescue the missing and treat the injured, and he demanded a thorough investigation, with accountability pursued in accordance with the law.

Xi also stressed that authorities across the country must draw lessons from the accident, remain vigilant regarding workplace safety, and intensify efforts to identify and eliminate potential risks in order to prevent major accidents.

As China has entered flood season, he also called for strengthened emergency preparedness and solid flood control and disaster relief measures to safeguard people's lives and property.

Premier Li Qiang also gave instructions on the rescue and accident investigation efforts. Li, who is also a member of the Standing Committee of the Political Bureau of the CPC Central Committee, urged the strengthening of workplace safety supervision across the country and called for a workplace safety overhaul in key sectors to curb the occurrence of major accidents.

Vice-Premier Zhang Guoqing has led a team to the site to oversee rescue operations and handling of the accident aftermath. The team said it will launch a "tough and uncompromising" investigation into the cause of the accident, clarify responsibilities in local management, industry supervision and corporate operations, and impose strict penalties in accordance with laws and regulations.

It also called on all regions and relevant departments to conduct a comprehensive review of mine safety measures and crack down on illegal and rule-breaking operations.

Authorities were instructed to carry out strict inspections and punish violations including concealed entrances in coal mines, falsification of safety monitoring data, unclear numbers of underground workers, and illegal subcontracting or contract transfers, according to the report.

Guo Xiaofang, head of the Qinyuan county government, said at a news conference on Saturday that initial inaccuracies in casualty figures were caused by chaos at the scene and the company's failure to provide an accurate head count of workers on duty. According to China Central Television, only 124 workers were registered in the system when the accident occurred, while the actual number of workers on duty was 247.

The company involved in the explosion was found to have "serious violations of laws" in an initial investigation. Those responsible have been placed under control, and all of the company's coal mines have ceased production, said Chen Xiangyang, mayor of Changzhi.