Mine director Eugeniusz Malobecki told the Associated Press that the individuals, whose names had not been released, were working about 350 yards underground at the Myslowice-Wesola complex when a loose electric cable fell on them as they were working in a shaft.

The killed colliery workers appeared to have died instantly, he said.

The fourth injured miner, Malobecki added, was last noted to be in stable condition at St Barbara's hospital in Sosnowiec.

According to a report on Polskie Radio Monday morning, all the men were employees of mine shaft construction and consolidation firm Kopex-PBS.

An investigation into the cause of the incident has begun.

Keep checking ILN for more information as it becomes available.