The Energy and Coal Industry Ministry of Ukraine has decided to conduct an off-scheduled internal audit of national joint-stock company Naftogaz Ukrainy in the period from November 26 to December 8, 2014.

The decision is stipulated in ministry order No. 837 of November 25, 2014 posted on the ministry's website.

"The goal is to define the correspondence to Ukrainian law, legal documents when Naftogaz Ukrainy made decisions in 2010-2011 to provide two interest-free loans to Chornomornaftogaz to buy two modern self-elevating floating drilling rigs worth UAH 6.443 billion," reads the document.

The audit is scheduled due to an application of an investigator sent to the ministry.

As reported, in May 2011 mass media reported that Chornomornaftogaz via an intermediary bought the Petro Hodovanets drilling rig for $400 million, while the producer from Singapore sold it at the price of around $250 million.

The opposition accused former energy and coal industry minister Yuriy Boiko of corruption when the rigs were bought.