A low-profile, patient counteroffensive led by a crack Ukrainian combat corps has pushed back Kremlin forces up to 15 kilometers (9 miles) in an eastern sector of the fighting front and potentially cutting off hundreds of Russian troops from supply and support. The Ukrainian ground gains and battle successes to the north of the fortress city Lyman have been step-by-step and incremental, the result of months of small-scale infantry assaults densely covered by strike and observation drones to route Russian defenders from positions, field reports and analysts say.JOIN US ON TELEGRAMFollow our coverage of the war on the @Kyivpost_official. The 3rd Army Corps, a major Ukrainian army formation with roots in a single, untrained volunteer civilian infantry battalion raised in Kyiv to help defend the capital in February 2022, is reportedly at the center of the offensive. Ukraine’s army has kept a tight lid on ongoing operations in the Lyman sector for months, practically banning media visits to front lines and only reporting the fact of heavy fighting, while confirming neither terrain gains nor losses. The sector – located between the Siverskyi Donets River, a major waterway, and the Zherebets River, a local barrier waterway – is covered with thick woods or swamp, intermixed with rolling hills, farmland and agricultural villages News and information feeds of formations assigned to the 3rd Corps and reviewed by Kyiv Post painted a consistent picture of successful offensive operations accompanied by heavy Russian casualties due to drone strikes, but as per Ukrainian Armed Forces’ (AFU) OPSEC rules, the information was presented without identifying geographical locations. Civilian rescue information networks monitored by Kyiv Post confirm continuing but limited Ukrainian losses in the sector.