(Reuters) – Ukraine’s gas transit operator said on Friday it was worried by reports of “gross interference” by Russian forces occupying a gas compressor station, and issued a new warning over supplies to Europe. The Novopskov compressor station in the Luhansk region of eastern Ukraine has been occupied by Russian forces and separatist fighters since soon after Russia invaded Ukraine on Feb. 24. Ukrainian gas pipeline operator OGTSU said at the time that the arrival of Russian troops could threaten gas supplies to Europe. OGTSU voiced new concern in a statement on Friday, citing reports of “gro…