US Vice President Kamala Harris met with Ukrainian President Volodymyr Zelenskyy during the Munich Security Conference in February and urged him to refrain from striking Russian oil refineries.

The Washington Post citing sources said that Harris' request "irritated" Zelenskyy and his aides.

The sources noted that the Ukrainian president "brushed off" these recommendations because he was not sure that they reflected the consensus position of the Joe Biden administration.

The newspaper adds that in the following weeks, Washington confirmed this warning in numerous conversations with the Ukrainian side. In particular, these statements were made by senior representatives of the Pentagon and US intelligence, as well as by Jake Sullivan, US National Security Adviser, who visited Kyiv in March.

However, since then, Ukraine has struck a number of Russian facilities, including an attack on 2 April on TANECO, Russia's third largest oil refinery, located in Tatarstan.

US officials say that supporting global energy markets to reduce inflation is a priority for the Biden administration ahead of the presidential election.

However, they say it is also important for maintaining European support for Ukraine's war effort.

"An increase in energy prices risks dampening European support for Ukraine aid," the US official said.

The US also doubts the military benefits of these Ukrainian attacks. In particular, the US military believes that the strikes do little to reduce Russia's combat capability and have led to a large-scale missile attack on Ukraine's power grid, which is much more damaging to Ukraine than the strikes on the refineries were to Russia.

The newspaper notes that the US position on strikes on Russian refineries has angered Ukraine, which considers such actions to be justified given Russia's continuous attacks on Ukrainian territory.

Ukrainian officials believe that these attacks are necessary to raise the price of Russian aggression and to emphasise that Russian society will not be safe until the war unleashed by Russia ends.

US Secretary of Defence Lloyd Austin recently criticised the Ukrainian strikes on Russian refineries, questioning their impact on the war.

Meanwhile, Europe believes that Ukraine has the right to strike Russian refineries. In particular, Estonian Foreign Minister Margus Tsahkna believes that Ukraine's attacks on Russian oil refineries are justified since they help curb Russia's revenues and make it harder for Russia to wage war.

Latvian President Edgars Rinkēvičs stated that Ukraine has every right to strike Russian oil refineries after the latest Russian attack on Ukraine

NATO Secretary General Jens Stoltenberg believes that Ukraine has the right to strike "legitimate military targets" outside its borders.