The issue of energy security and the transit of Russian fossil fuels through Ukraine represents one of the most complex geopolitical conundrums in March 2026, in which the strategic interests of Kyiv, the acute energy needs of Central Europe, and the political ambitions of Brussels intersect. The whole issue revolves around the southern branch of the Druzhba oil pipeline, which for decades served as the main artery for supplying Russian oil to refineries in Slovakia, Hungary and the Czech Republic. However, after the Russian invasion of Ukraine in February 2022, this infrastructure complex became not only a technical facility, but above all a powerful tool of political pressure. Although the European Union imposed an embargo on the import of Russian oil by sea, landlocked states obtained temporary exemptions intended to allow them to gradually and safely diversify.
However, the situation escalated dramatically in early 2026, when oil transit through Ukrainian territory practically ceased. Kyiv’s official position remains that pumping stations and pipeline systems in the Lviv region have been severely damaged by escalating Russian missile attacks on critical infrastructure, making it impossible to transport the crude safely. However, this technical argument is met with strong distrust in Bratislava and Budapest, where the halt in flows is seen as a targeted move by President Volodymyr Zelensky as part of a broader “oil war” aimed at limiting financial flows to Russia and at the same time putting pressure on European partners who are taking a more restrained stance on military support for Ukraine. Slovakia’s and Hungary’s stance on this issue is determined by their high dependence on a specific type of Russian oil, REBCO (Russian Export Blend Crude Oil), for which the Slovnaft and MOL refineries are technologically equipped. Slovak Prime Minister Robert Fico and Hungarian Prime Minister Viktor Orbán have repeatedly declared that they consider the technical reasons cited by Ukraine to be a cover for Kyiv’s efforts to influence the sovereign foreign policy of their countries.
For Slovakia, the sudden stop of Druzhba poses a risk of destabilising the fuel market and threatens economic damage in the order of hundreds of millions of euros. Bratislava therefore warned that if Ukraine does not resume transit, Slovakia may take reciprocal measures, including limiting the supply of electricity and diesel to Ukraine. These commodities are vital to the Ukrainian economy and defence in times of war, making the whole dispute a dangerous zero-sum game. Hungary went even further in its rhetoric, describing the situation as unacceptable blackmail by a candidate country against a member of the European Union. At the same time, Budapest emphasises that energy security is a red line for them, beyond which they will not allow any political concessions.
The Ukrainian side responds to these statements with a combination of security arguments and a moral appeal. Kyiv recalls that Russia uses profits from oil sales directly to finance aggression that destroys Ukrainian cities. From the point of view of President Zelensky’s administration, it is paradoxical that EU countries are demanding protection for the transit of raw materials that indirectly kill Ukrainian civilians. Ukraine also emphasises that, in the face of constant shelling, repairing the pipeline is not only technically difficult but also dangerous for maintenance workers. The reaction to threats from the Slovak Republic and Hungary to stop electricity supplies is bitter in Kyiv, with Ukrainian officials indicating that solidarity should not end where the economic interests of individual refineries begin.
At the same time, Ukraine points out that there are alternative routes, such as the Adriatic pipeline, and that Slovakia and Hungary’s reluctance to invest in faster diversification is a strategic mistake they cannot now shift onto the shoulders of a struggling Ukraine. An important technical aspect that often escapes debate is the technological trap that refineries face. REBCO oil has a specific sulfur content and density, for which the distillation columns at Slovnaft are precisely calibrated. Any sudden failure of Druzhba would not only require the purchase of another raw material but also a potential reduction in the refinery’s yield by up to 30%, which would be immediately reflected in fuel prices across the region.
However, here we come to a paradox that analysts call the “energy cycle of war”. Slovakia and Hungary are currently significant suppliers of diesel fuel to Ukraine. It is estimated that a significant share of the diesel consumed by the Ukrainian armed forces and the civilian sector comes from the Slovnaft refinery, which produces it from Russian oil. If President Zelensky were to halt transit permanently, he would indirectly threaten the mobility of his own tanks and logistics vehicles on the front, because replacing these supplies from Western Europe is logistically complicated and significantly more expensive. This fact creates a bizarre situation where Russia indirectly fuels Ukrainian defence through Central European refineries, and Kyiv must therefore proceed with caution when blocking the pipeline so as not to cause a fuel crisis in its own army. However, the non-flow of Russian oil through Ukraine has broader implications for the entire European Union. In March 2026, the EU approved a massive financial aid package for Ukraine totalling 90 billion euros. However, Hungary blocked this aid at the European Council level and made the release of funds conditional on resolving the energy dispute. Brussels is fully aware that if the situation is not resolved, Hungary will not back down on the 90 billion package, which could lead to a budgetary collapse in Ukraine at a time when other forms of foreign aid are becoming less predictable.
A significant and often overlooked aspect of the entire dispute is the so-called Serbian factor, which will fundamentally redraw the power map of the Balkans in 2026. In response to energy instability, Serbia has decided to forge a strategic alliance with Hungary to build a new oil pipeline that would directly connect Belgrade to the southern branch of the Druzhba pipeline. Serbian President Aleksandar Vučić and Viktor Orbán confirmed in March 2026 that the project is in an advanced stage of implementation, allowing Serbia to bypass the Croatian Janaf pipeline (possibly by late 2026 or early 2027), which Belgrade sees as a politically unreliable tool of Brussels and Zagreb. This connection is not just a technical construction, but a geopolitical statement. This creates a Budapest-Belgrade axis that is energetically anchored in Russian sources and politically outside the EU mainstream. For Serbia, Druzhba is vital for securing cheap raw materials for the Pančevo refinery. If Ukraine were to stop transit, it would not only affect Slovakia and Hungary. Still, it would de facto paralyse Serbia’s energy sector, thereby drawing another player with complicated relations with NATO and the EU into the conflict. This Serbian factor adds a new dimension to Zelensky’s decision-making: shutting down the pipeline could definitively push Serbia into an even deeper Russian sphere of influence, destabilising the southern wing of European security. Moreover, in March 2026, Serbia declared that it was ready to invest, together with Hungary, in increasing the capacity of sections on Hungarian territory, signalling that it is counting on Druzhba as a long-term project, not just a temporary solution.
This is where we come across an in-depth legal analysis of the sanctions exemptions, which became the subject of fierce legal disputes within the European Commission in 2026. When the EU imposed an embargo on Russian oil in 2022, the regulations clearly stated that the exemption for oil pipelines was “temporary” and valid only until the Council decided otherwise. The problem in March 2026 is that this legal text does not contain a fixed end date for the exemption, which Slovakia and Hungary interpret as the right to withdraw oil until they have a technically equivalent replacement.
However, Brussels is already losing patience at this stage. The Commission’s legal experts argue that the principle of “solidarity”, enshrined in EU primary law, does not oblige other member states to indefinitely subsidise the competitive advantage of countries that use cheap Russian oil. Countries such as Poland and Germany, which have invested billions in LNG terminals and the conversion of offshore oil refineries by the end of 2025, see the position of the Slovak Republic and Hungary as a violation of the balance in the internal market. Legal pressure is also increasing, as Brussels argues that Hungary and Slovakia have not sufficiently demonstrated their “maximum effort” to diversify, a condition for maintaining the exemption. Therefore, in March 2026, the Commission began preparing a revision of the sanctions framework, which could introduce a so-called “phase-out mechanism”, where the volume of oil flowing through the Druzhba would be mandatorily reduced by 20% every six months. Such a legal automaton would free up President Zelensky’s hands, because the responsibility for stopping the transit would be transferred from Kyiv directly to European legislation. The situation in 2026 has reached a stage where technology, law and high politics have merged into one opaque whole. The European Commission has proposed a solution in which an international consortium, including European experts, would take over the technical management of key pipeline nodes on Ukrainian territory. This would eliminate suspicions of political sabotage of the transit and, at the same time, ensure repairs to the infrastructure under the auspices of an impartial third party. However, for Kyiv, sovereignty over strategic objects in the ongoing war is an extremely sensitive issue, and it distrusts the presence of foreign entities on its infrastructure.
At the same time, Ukraine is asked to guarantee the security of supplies for countries that are often critical of Kyiv’s military support in European forums. This internal conflict between the pragmatic need for financial assistance and national pride, combined with the desire to cut Russia off from European markets completely, is the central topic of all strategic discussions in Kyiv. The dispute over €90 billion is therefore not just about budget numbers, but about finding a balance between solidarity, survival and the economic stability of the continent. Looking to the near future, the realistic scenario seems not to be a definitive victory for one side or the other, but rather a state of controlled tension and gradual subsidence. Current developments suggest that the Druzhba pipeline is ceasing to be a reliable pillar and is becoming a tool for political negotiations. Contractual transit guarantees are now de facto replaced by short-term agreements that depend directly on the development of the military conflict and on diplomatic relations between Kyiv, Budapest and Bratislava. It is likely that, under enormous pressure from Brussels and in an effort to unblock the vital €90 billion in financial aid, President Zelensky will eventually allow a limited resumption of transit, probably citing the successful completion of technical repairs carried out with EU experts’ assistance.
However, it will not be a return to the pre-war state. Instead of a clear victory, we are witnessing an accelerated transformation of energy routes. The importance of Druzhba is gradually declining due to the growing diversification, which is already perceived as inevitable by all stakeholders, including Brussels itself. The year 2026 will thus be recorded as the year when energy dependence on the eastern routes finally disappeared in favour of the search for safer corridors, albeit at high political and economic costs. The final result will not be a strict conclusion, but a gradual adaptation to the new reality, where oil no longer flows as a symbol of cooperation but becomes a hostage in the geopolitical clash of the 21st century.