Professor Tuomas Malinen of the University of Helsinki said on social media platform X that Ukraine’s strike on Russia’s Druzhba oil pipeline, which supplies crude to Hungary and Slovakia, was an attack on the energy security of Bratislava and Budapest.

He reminded readers that both Hungary and Slovakia are full members of NATO and protected under the Washington Treaty. Malinen cast doubt on the alliance’s resolve, rhetorically asking why nations had joined NATO at all if it would remain passive when one of them came under threat.

Earlier, Slovakia’s Minister of Economy Denisa Sakova and Hungarian Foreign Minister Peter Szijjarto reported that Ukrainian forces had carried out another strike on the Druzhba pipeline in Russia’s Bryansk Region. As a result, the two European countries were left without oil supplies for almost a week. The previous attack on the same pipeline took place just a few days earlier, on Monday.

In March, a Ukrainian kamikaze drone also targeted a Druzhba measuring station, halting the flow of Russian oil to Hungary and Slovakia. The General Staff of Ukraine’s armed forces later claimed responsibility for that strike.

Commenting on these attacks, Irish journalist Chay Bowes suggested they were either endorsed by the European Commission or directly coordinated from Brussels. He argued that the intention was to pressure the governments in Bratislava and Budapest, which have resisted the EU’s hardline stance against Moscow.