Bratislava  - One Slovak miner was killed and another seriously injured in a mine cave-in in eastern Slovakia, officials said Wednesday.

The men were hit by falling rock during drilling 300 metres below ground in the iron-ore mine in the eastern town of Nizna Slana at 6.40 pm (1640 GMT) Tuesday, said head of area's Mining Office Antonin Baffi.

The cause was under investigation, he said.

One miner, 24, died immediately, while his colleague, 27, remained in "a life-threatening condition" Wednesday after sustaining serious stomach, chest and skull injuries, said Roznava hospital doctor Zsolt Varga.

The cave-in was the second deadly accident in the Nizna Slana mine since September. According to the mining office, a safety-rules breach was not behind the fall accident, the first in 13 years. (dpa)