A series of attacks inside Russian territory and unexplained explosions at Russian targets near the border with Ukraine have expanded the scope of the conflict in recent weeks, underscoring Russian vulnerabilities in regions that are crucial to Moscow’s renewed offensive in eastern Ukraine.
Russian officials said last month that two Ukrainian Mi-24 helicopters entered Russian airspace flying at low altitudes to evade air defenses and launched a missile attack on a fuel depot in Russia’s Belgorod region, a province that sits on the western edge of the country, less than 20 miles from Ukraine’s war-ravaged city of Kharkiv.
