Twenty-three people died and three others were injured Sunday in an explosion at a coal mine in the Karaganda region, officials said.

Eighty-seven miners were working at the mine in the town of Shakhtinsk (search) about 120 miles south of the capital, Astana (search), when the blast occurred at 3:08 a.m., said regional administration spokesman Zhanibek Sadykanov.

Two injured miners were hospitalized and a third was released after treatment, he said.

President Nursultan Nazarbayev (search) sent a letter of condolence to the families of the victims and ordered the government to pay them compensation, as well as carry out a full investigation, officials said.

Sadykanov said a special commission was investigating the cause of the blast.

Rescue operations were complete and work had started on restoring the mine, which is owned by Kazakhstan's ISPAT-Karmet metal giant, said Nakyp Kapbasov, deputy regional emergencies agency chief.

At least eight people have died in mining accidents in the central industrial Karaganda region this year.