SOFIA, Bulgaria (AP) — Officials say a landslide in a coal mine in southwestern Bulgaria has killed at least two miners and two others are missing.

The chief of the local fire brigade Georgi Parmakov confirmed on Tuesday that the bodies of two miners have been recovered. A rescue team is removing the rocks in the search for the other two.

It is the fourth major accident in the Oranovo mine in the past eight years. Union leaders said the reason for the collapse was poor safety standards. The mine management has not made any statements yet.