KYIV, March 25 - Ukrainian police are investigating two companies and a factory over a coal deal which some anti-corruption campaigners say epitomizes the difficulties of doing business in the east European country, Reuters reported.

The sums involved in the deal are small but the Anti-Corruption Action Centre, an independent watchdog, says it illustrates the lack of transparency in Ukrainian business, an issue in a presidential election on Sunday that has cost President Petro Poroshenko support.

State-run coal company Volynvuhillia ordered the Novovolynska-9 mine it oversees in Novovolynsk, northwestern Ukraine, to sell coal to privately held Ukrainskiy Natsionalniy Product (UNP), company documents show. A contract was agreed in December 2017 and sales began two months later.

Volodymyr Yurkiv, the mine’s director at the time, told Reuters he complained to the energy ministry about the contract because it allowed UNP to pay eight percent less for its coal than the minimum price set by the ministry for private buyers.

He and trade unions also protested to the ministry when miners went unpaid as Volynvuhillia spent on other projects and went into the red. Police are now probing Volynvuhillia over the non-payment of 5.9 million hryvnias ($220,000) in salaries from July 15 to Sept. 5, 2018, suspecting unnamed UNP officials of lining their pockets while the miners struggled to make ends meet, according to court documents. Police declined to name the officials.

Energy ministry figures show wage arrears in state mines had reached 138.8 million hryvnias by Jan 1. Former Finance Minister Oleksandr Danylyuk told Reuters the arrears were largely caused by company officials spending money that should go to salaries on big purchases such as equipment because of the kickbacks that often go with such purchases.

Asked about the sales contract with UNP, Andriy Pylypiuk, acting manager of Volynvuhillia, said the coal purchase price in the original contract was an error that was corrected after the deal and that UNP quickly started paying more for its coal.

Company documents seen by Reuters confirmed the price increase.

Pylypiuk said his company supported selling to UNP because no other firm wanted to buy coal from Novovolynska-9 and that UNP had offered to pay up front. He denied wrongdoing.

Andriy Dombrov, who owns UNP, declined to answer Reuters’ questions. Police provided no details of how the investigation is going. The energy ministry declined comment. (rt/ez)