France, Aug. 27 -- Central Europe has been plunged into fresh energy anxiety after a series of Ukrainian drone strikes disrupted the flow of Russian oil through the Druzhba pipeline, igniting a war of words between Kyiv, Budapest and Bratislava.

In 2022, after Russia invaded Ukraine, the European Union imposed a ban on most oil imports from Russia.

But the Druzhba pipeline was temporarily exempted from this, in order to give landlocked Hungary and Slovakia time to diversify their supply.

But when Ukrainian drone strikes hit a "fuel infrastructure facility" in Russia's Unechsky district in mid-August, according to Aleksandr Bogomaz, the governor of the country's western Bryansk region where the district is located, this forced temporary...