Three workers died in the Southwestern town of Blagoevgrad when mud slid down into the dig where they were working.

The victims were changing sewer pipes in a five-meter deep dig when the mud slid, Focus news agency reported. Water supply and sewer company ViK Blagoevgrad ordered the pipe repairs.

According to the emergency centre in Blagoevgrad, the ambulance reached the place six minutes after tip-off for the accident, but the men had already been dead. In cases when a victim has been buried under mud, he could survive for only three to five minutes and would die because of a lack of oxygen, the medics said.

The remains of the three victims, aged 32, 34 and 47, would be taken out of the mud after it would have been stabilised.

Police was investigating the reasons for the mud sliding. The incident was most probably caused by the lack of strengthening facilities along the dig.