TAIYUAN, May 7 (Xinhua) -- Rescuers have recovered the bodies of another five miners who were trapped in Saturday's gas blast in a coal mine in Linfen, a coal-rich city in Shanxi Province, north China, bringing the confirmed death toll to 28.

The fate of other two trapped miners is not known yet as rescue efforts continue, according to rescue headquarters.

About 100 rescuers are trying to provide ventilation to the shafts, they said.

"Rescue work is quite difficult since the shaft is still filled with smoke," said Zhao Tiechui, director of the State Administration for Coal Mine Safety Supervision, at the scene on Sunday.

The gas blast occurred around 1:50 p.m. on Saturday at Pudeng Coal Mine in Kecheng township of Puxian county where 125 miners were working.

Ninety-five miners, including 23 who were injured - one seriously, escaped, according to a press release given by Shanxi Provincial Bureau of Work Safety on Sunday.

Bureau sources said the coal mine had been earlier ordered to suspend production but mine operators resumed production on Friday without a permit.

"The coal mine was in a mess and under poor management," said the provincial work safety watchdog, adding that the 125 miners who were working underground at the time of the blast had been hired by five different mining contractors.

Local police have put the coal mine owner and several managers under surveillance. Provincial officials have ordered an investigation into the explosion.

Pudeng Coal Mine, with an annual production capacity of 150,000tons, was set up in 1986 by a village and became a private venture in 2004.

The Pudeng explosion is the second colliery accident within six days in Shanxi, China's largest coal producing province. On Monday, a blast in an illegal mine at Liujiacun village, Yuxian county, killed 14 people.

Shanxi boasts of coal reserves topping 264 billion tons, amounting to 26 percent of the national figure. It produces about 600 million tons of coal a year.