Four miners were killed after a tremor at a coal mine in southern Poland on Saturday and rescuers were still trying to reach six others trapped underground, the mine's owner JSW said.
"The doctor confirmed the death of two more miners... The tragic balance sheet of yesterday's high-energy tremor at the mine increased to four people," JSW said in a statement on Sunday.
The company had earlier announced the deaths of two of the miners.
The tremor shook JSW's Borynia-Zofiowka mine on Saturday morning. There were 52 workers in the area, 42 got out on their own, and 10 remained underground.
After many hours, rescuers reached four miners late on Saturday but they did not show any signs of life, JSW said earlier.
"The conditions allow us to continue the search for our six colleagues," JSW Chief Executive Tomasz Cudny told reporters on Sunday.
This is the second accident in a week at a coal mine owned by JSW. Last Wednesday, five people died and seven were trapped in the Pniowek coal mine in southern Poland after an explosion.
Polish Prime Minister Mateusz Morawiecki, who visited the Borynia-Zofiowka mine on Saturday, said that all procedures in both mines will be "thoroughly checked" by a special commission.