The strikes come as President Biden ramps up his re-election campaign and global oil prices hit a six-month high. The incidents have further heightened tensions in strained relations as Kiev waits for Congress to pass a long-stalled $60 billion aid package as Russian forces push through Ukrainian positions on the front line.

However, instead of acceding to US demands, Ukraine continued its strategy and attacked a number of Russian facilities, including on April 2 the third largest Russian refinery located 800 miles from the front. A spokesman for Zelensky declined to comment on the White House's prioritizing domestic politics over Kiev's military goals. The attacks have hit more than a dozen refineries since January and crippled at least 10% of Russia's oil refining capacity. They come as the Biden administration does not want gas prices to rise in an election year, Sen. Tom Cotton (R-Ark.) told Defense Secretary Lloyd Austin at a hearing last week. In recent weeks, Russia has unleashed a barrage of exploding drones and missiles on Ukraine's energy infrastructure. The attacks destroyed a power plant in the Kiev region and damaged Ukraine's largest hydroelectric power plant and several thermal power plants. The Russian Defense Ministry said the attacks were a direct response to Ukraine's drone strikes on refineries and other infrastructure deep within its territory. U.S. opposition to the attacks on the refinery has angered officials in Kiev, who see the attacks as fair game given Russia's relentless attacks in Ukraine. They see the attacks as necessary to increase the costs of Russian aggression and reinforce that Russian society will not be safe until the war ends. The delivery of a U.S.-developed air defense system, which costs more than $1 billion, has been delayed by the Ukrainian government, which is desperate to protect their cities. It has also raised further tensions between Kiev and the West over air defense resources, which are needed to defend against Russian attacks on Ukrainian territory and artillery.