Border police officers, tax inspectors and customs officials will begin an inspection of Russian oil giant Lukoil’s oil port located near the Bulgarian Black Sea city of Burgas on Wednesday.

The inspection should gather “complete information” about the operation of the oil terminal, caretaker Economy Minister Asen Vassilev told broadcaster Free Europe in an interview. Lukoil received a 35-year concession in 2011, granted by former prime minister Boyko Borissov’s first government.

The authorities will verify whether the Russian oil giant has been declaring its corporate tax correctly, and particularly whether the Russian oil is first being transferred to another country and then to Bulgaria at higher prices. This would make it possible for the company to hide its profits from the country where the oil is actually used.

Lukoil, which owns the largest oil refinery on the Balkan Peninsula which is also located near Bourgas, has paid almost no corporate tax to the state in the last decade and usually ends the financial year at a loss.