Officials say a methane explosion has killed three and wounded seven people in western Georgia.

Interior Ministry spokesman Zurab Gvenetadze said an explosion occurred in a mine some 300 kilometers (miles) west of the capital Tbilisi late Friday evening. State-owned Georgian television quoted hospital officials as saying the wounded are all in a critical condition.

The Interior Ministry said the cause of the accident has yet to be established.

This is the second explosion at the same mine this year. A sudden build-up of methane in March left four miners dead.

Mine blasts are rare in Georgia.