The inter-city train from Warsaw to Katowice was derailed at the town of Baby, near the city of Piotrkow Trybunalski, emergency services said.

The engine and three of the carriages went off the tracks. It was not clear what caused the derailment. Initial reports said four people had died, but police later revised the figure.

The accident happened at about 16:15 (14:15 GMT), around two hours after the train left the capital Warsaw.

"We heard a huge noise," passenger Marcin Chlebowski told Poland's TVN24 news channel. "The first wagon was completely destroyed, windows smashed and its sides smashed. People remained calm - many were in shock - and rescue crews arrived rapidly."

The first carriage was reported to be lying on its side. Firefighter Wlodzimierz Kapiec told TVN24 that the death toll could rise.

Polish PKP railways spokesman Lukasz Kurpiewski told TVN24 that about 280 passengers were believed to have been on board the train.

Authorities said the driver would be questioned but had been badly shocked by the accident.