"The rescue is difficult and complicated," firefighter Jaroslaw Wojtasik told Polish television.

"The damage to the wagons is huge. We have contact with victims. We are approaching very cautiously."

"I felt the blow," said an unnamed survivor. "I hit the person before me. The lights went out. Everything flew. We flew over the compartment like bags. We could hear screams. We prayed."

-- Reported by Reuters