SHANGHAI (AFP, REUTERS) - Nine more Chinese miners trapped underground for over two weeks have been confirmed dead, local government officials said on Monday (Jan 25), leaving one unaccounted for after a blast at the site.

A group of 22 were trapped hundreds of metres underground by an explosion at the Hushan mine in eastern Shandong province on Jan 10, with some relying on food and medicine delivered through long shafts drilled by rescue teams.

Eleven survivors were finally brought to the surface on Sunday, in a major breakthrough for a rescue operation that has captivated the nation.

"From Sunday afternoon to this afternoon, rescue workers have not stopped searching, and found a further nine trapped miners who unfortunately all died," Yantai city mayor Chen Fei said at a briefing on Monday. "Along with one miner who died on Thursday, the bodies of the nine deceased miners were all lifted out of the mine."

Rescue teams will not stop searching until the last remaining miner is found, Mr Chen said, adding that high underground water level in a section of the mine had complicated rescue operations.

The initial explosion occurred in the mine's ventilator shaft, causing a blockage that damaged the cable car.

Mr Chen said that all nine miners had been killed by the impact of a secondary explosion in the mine on Jan 10 as they were trying to escape, judging from their positions.

Rescue operations sped up dramatically on Sunday as a blockage in the ventilator shaft was cleared.

Contact was first established a week ago with a group of 11 miners trapped in a section of the mine around 580m below the surface.

One of them was seriously injured in the initial explosion and died after falling into a coma. Another miner was found alive by rescuers as they attempted to reach the group.

Those who were brought to surface on Sunday were rescued much earlier than expected, thanks to steel pipes supporting blockages in the mine shaft, according to state media.

An air ventilation shaft, which was the most feasible way to bring up the workers, had been cleared to a depth of 368m, Mr Xiao Wenru, chief engineer for the mine rescue, told Xinhua News Agency on Monday.

"It is at this location we discovered that there were some steel pipes supporting the blockage... there is almost no blockage under the steel pipes," he said.

Mr Xiao had said on Sunday that there had been a breakthrough in rescue efforts after clearing some blockages and finding the "cavities underneath".

The 11 miners rescued on Sunday were mostly in good condition, after 14 days trapped underground.

Officials had earlier said the trapped workers may have to wait another 15 days before they could be rescued due to a blockage along their intended escape route. The workers had been able to receive medical and food supplies while they were trapped.

Mining accidents are common in China's dangerous and poorly regulated sector, and the country's mines are among the world's deadliest. China recorded 573 mine-related deaths in 2020, according to the National Mine Safety Administration.