Public joint-stock company Ukrtatnafta (Kremenchuk Oil Refinery, which is under the control of Privat Group, has demanded that Ukrtransnafta, where the state is represented by national joint-stock company Naftogaz Ukrainy which had its management restored in May, to vacate oil reservoirs leased by the company and pay UAH 107.5 million of debt owed for leasing from April until June 10.

"We demand to urgently pay the debt for leasing, terminate the leasing agreement of April 1, 2015, vacate Ukrtatnafta's reservoirs and present the reference details or proposals on pumping of oil belonged to Ukrtransnafta from the reservoirs," reads a letter issued by the refinery dated June 10, which has been posted on its website.

Ukrtatnafta denies the claims of Ukrtransnafta which were presented in its letter of May 29 that the quality of oil changed and the refinery used it. According to Ukrtatnafta, crude oil is fully in line with GOST 9965-76 standards and was restored properly.

Ukrtatnafta said in its letter that due to storing oil in the interests of Ukrtransnafta, the company failed to buy crude oil for own needs in enough volumes and daily refining at Kremenchuk Oil Refinery fell by 20%.