Bulgarian Transport Minister Ivaylo Moskovski on Monday ordered an internal inquiry into suspected theft of diesel fuel at cash-strapped state railways company BDZ following a media report.

The company’s diesel expenses have increased this year compared to the 2014 levels by approximately two tank rail cars a month, according to an investigative report by Nova TV station aired on Sunday.

A typical tank rail car can carry 65 tons of fuel.

A former train driver, held in police custody over suspected fuel theft, has revealed to Nova that the criminal scheme has been allegedly ongoing for years with many low-level employees involved. Shift managers were reportedly accepting bribes for putting drivers on shifts at train stations with little or no control.

BDZ has been faced with considerable financial problems over the years. In 2012, an organized criminal group was accused of stealing 30 to 50 tons of diesel per month at locations near Bulgaria's border with Turkey.

BDZ's CEO Vladimir Vladimirov recently announced the company had to cancel 38 passenger trains to cut losses. However, mass public protests forced BDZ to reconsider its decision. 

The government announced additional funding of BGN 40 M for BDZ last week in order to prevent staff cuts and the cancellation of trains. 

The results of the internal investigation at BDZ will be submitted to the Prosecutor's Office, the Transport Ministry said in a statement.