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.
At a Gazprom service station on the motorway between Novi Sad and Belgrade, Bojan and his colleagues were taking no chances, pumping the petrol and diesel for their customers. A cash machine has been installed inside the service station just in case.
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.
The situation impacts not only Serbia's fuel supply but also its political relationships within the Balkans, as seen with neighbouring Bulgaria and Hungary, which are taking alternative measures to address their energy dependencies.
As Serbia contemplates its actions, President Vucic's administration is left with tough decisions regarding its long-standing affiliations with Russia and its future aspirations for joining the European Union.
