Hungary and Slovakia, in a letter sent to Brussels, have urged the European Commission to "act against Ukraine's repeated attacks on the Druzhba oil pipeline", Hungarian Foreign Minister Peter Szijjarto said.
"Such attacks are a direct and unacceptable assault on our energy security," Szijjarto posted on X, accusing the commission of remaining "silent".
A Ukrainian strike hit a "fuel infrastructure facility" in Russia's Unechsky district, according to Aleksandr Bogomaz, the governor of western Bryansk region.
He did not directly name the pipeline, but an important pumping station for Druzhba - Russian for "friendship" - is in the district and has been targeted many times.
Hungary's Prime Minister Viktor Orban also said on Friday that he had complained to US President Donald Trump after Ukraine's military actions against Russia's war disrupted oil supplies.
Hungary has repeatedly seen its oil supplies via the Druzhba pipeline cut, with the third disruption in recent days reported on Friday.
"I asked for the help of the American president. The Ukrainians keep shelling the Friendship oil pipeline," Orban said, according to a Facebook post by his Fidesz party on Friday. He said that Trump replied, expressing support.
Hungarian energy company MOL said in a statement that the "security of supply continues to be guaranteed".
Ukrainian Foreign Minister Andrii Sybiha on Monday said Hungary should complain to its "friends in Moscow" over the oil disruptions.
"It is Russia, not Ukraine, who began this war and refuses to end it," he posted on X.
But the Druzhba pipeline was temporarily exempted to give landlocked Central European countries time to diversify.
Orban and his Slovakian counterpart Robert Fico have regularly slammed the sanctions, citing energy security.
