An impasse over Russian oil and imminent US sanctions has put Serbia at loggerheads with its traditional ally in Moscow.


Added differences over Russian gas supplies and Serbia's arms trade have ramped up the tensions, with Serbian President Aleksandar Vucic trading barbs with the Kremlin.


The root of the problem, and the most pressing issue, is the fate of Serbia's national oil company.


Russia's Gazprom and Gazprom Neft own more than half the shares of Petroleum Industry of Serbia (NIS). That has put the company in a tight spot, after US sanctions on NIS came into effect last month over its ties to Russia's energy industry.


Serbian Energy Minister Dubravka Djedovic Handanovic has told the BBC that NIS's Russian owners have now asked the US for a waiver, which indicated the Russian side was ready to transfer the control and influence upon the company to a third party. But she warns time is running out.


The impact of US sanctions on NIS has been immediate. Its petrol stations have put up signs warning customers that Visa and Mastercard can no longer be used to pay for fuel, as the US credit card giants have stopped processing payments.


NIS operates both of Serbia's oil refineries, providing more than four-fifths of its petrol and diesel, and almost all its jet and heavy fuels.


Serbia is landlocked, so it relies on Croatia to deliver oil via its Janaf pipeline. But since sanctions kicked in, the flow has been cut off.


The refineries will run out of crude to process before the end of November, which is why the energy minister says time is running out.


Serbia's struggle with US sanctions is echoed in neighboring countries. Bulgaria has enacted legislation to take over its only oil refinery from Lukoil ahead of sanctions, and Hungary has secured a waiver from President Trump.


The situation appears critical, as national airline Air Serbia is adjusting business operations amidst the fuel supply concerns, highlighting the urgency for effective solutions to maintain essential services.


As Serbia looks to bridge its energy deficits, the implications of these sanctions stretch beyond the energy sector, potentially influencing Serbia's future geopolitical alignment and relationships within the EU framework.