China’s top leader, Xi Jinping, called on Saturday for a redoubled rescue mission in northern China after a gas explosion in a mine there killed at least 82 people, the Chinese state news agency said, in what appeared to be one of the deadliest Chinese mining disasters in years.

Mr. Xi “stressed the need to make every effort to treat the injured, organize search and rescue operations scientifically and properly handle the aftermath,” the agency, Xinhua, reported. He also called for an investigation into the explosion, which happened Friday night, and emphasized the need to “hold those responsible to account, according to the law.”

Mr. Xi’s decision to quickly and personally issue a statement was significant and may have indicated that Chinese officials expected the situation to worsen. The Chinese government often keeps back details of accidents while it gathers information and prepares to issue a response. But soon after Mr. Xi’s statement on Saturday, the official death count began to rise drastically, with new tolls announced every few minutes.

However, the latest death toll of 82 people was a correction by officials to an earlier count of 90 reported by state media. The head of the county, speaking at a news conference late on Saturday, said the chaos of the scene and unclear numbers on the company’s work force led the government to get the initial toll wrong.

Additionally, two people are missing, and 128 are hospitalized with injuries, the officials said at the conference.

Xinhua initially reported eight deaths and said that more than 200 of the 247 workers who had been underground when the explosion occurred had been safely recovered.