A cargo train, composed of 23 tankers, was entering the railway station of Hitrino, a village in northeastern Bulgaria, when twelve of the cisterns went off the track and one exploded.

At least seven people lost their and twenty-nine others were injured. Dozens of houses were damaged or destroyed. 

Twenty of the containers had propylene and three were loaded with liquefied petroleum gas. The composition was headed to Ruse, operated by Bulmarket, the first private company granted license for cargo transportation.

Of the twelve tanks left stuck in the center of Hitrino (with the village's rail line crossing it down the middle), nine are full of propylene and the rest with LPG.   

A manoeuvre was required at the Hitrino railway station to give way to a passenger train, police and local officials say.

However, the four cisterns derailed as the train was making a turn to enter another track, with Hitrino mayor Nuridin Ismail blaming the development on high speed.

According to Transport Minister Ivaylo Moskovski a man working at the station, who was to regulate the train's entry and manoeuvres and sustained burns on the hands in the incident, argued sparks could be seen coming out of the locomotive as it was arriving to the station.

In Moskovski's words, sparks could appear after an attempt to briskly slow down the train.

Neither claim was immediately verified.

Police data, cited by the Bulgarian National Radio, suggests the last two waggons of the cargo train entered in contact with the electricity grid.

With the train driver having survived and testifying before authorities, more details on the development are expected soon.