A group of experts have been sent by China's cabinet, the State Council, to north China's Hebei Province, to investigate Saturday's mine fire, which has killed at least 61 people, while 4 others still missing.

Headed by vice director of the State Administration of Work Safety, the team will look for more evidence on the cause of the fire, information on casualties and economic losses, China Radio International reported Wednesday.

Preliminary investigation shows the fire started in the ignition of an electronic cable in one mine, and the flames quickly spread to four other iron mines.

Owners of the mines are under house arrest.