Four people were killed and 22 people sustained injuries of varying severity as a result of a RegioJet 1021 night express head-on collision with a ČD Cargo freight train at the new Pardubice train station, iDNES.cz reported on Thursday, citing the local police.

It is not yet possible to speculate about the causes of the accident, Czech Transport Minister Martin Kupka said.

RegioJet also commented on the accident.

"Rescue work is underway at the site with the deployment of all rescue units. The owner of the company, Radim Jančura, and other employees of the carrier are also present," the company said.

"I want to express my great regret for myself and RegioJet for this tragic event, especially for the loss of human life. Deep condolences to all their loved ones," Jančura said.

Ukrzaliznytsia said on Thursday morning that the train contained trailer cars carrying RegioJet passengers to Chop, Zakarpattia region. According to preliminary information, there were no deaths or serious injuries among passengers heading for Chop, since the trailer cars are inside the train, and were not damaged as a result of the collision.

"Ukrzaliznytsia is in contact with the Czech operator to provide maximum assistance to passengers with subsequent transfers. Details of the accident are being clarified," the company said.