Russia establishes security zone in Ukraine's Sumy region

Russian forces are working to establish a 'security strip' or buffer zone in Ukraine's northeastern Sumy region, following operations that reportedly drove out Ukrainian troops from neighboring Russia's Kursk region. The Russian Defense Ministry claims to have completed the defeat of Ukrainian forces in Kursk and is focusing on securing the Sumy border, although Ukraine disputes a full withdrawal and maintains some presence in the area. Several border villages in Sumy are now under Russian control, while analysts and official reports describe parts of the region as a contested 'grey zone' where neither side holds full authority. Ukrainian officials acknowledge some Russian advances but assert that Moscow has made limited progress in establishing the buffer zone. Open-source battlefield monitors estimate that around 32–52 square miles of Sumy remain contested. Meanwhile, Ukrainian forces are reportedly building defensive lines in anticipation of further Russian offensives.