Volodymyr Zelensky is hoping to rally support from European leaders at a summit in Brussels on Friday, as Donald Trump threatens to cripple the Ukrainian war effort by buying Russian diesel.

Ukraine’s resumption of strikes on Russian refineries is a “disgrace” that keeps global energy prices elevated, U.S. President Donald Trump told the Newsmax news outlet in an interview aired on Thursd...

Russia is not known to have made any concession in exchange for Mr. Trump’s decision to lift diesel sanctions, and the move has not yet eased the pain at the pump.