Ukrainian forces attacked two key Russian air bases behind enemy lines on Tuesday, with Western officials saying that long-range missiles known as ATACMS were used in the strikes.
Russia’s assault there may be a sign that Moscow is trying to regain the initiative in the war, after it spent months defending against Ukraine’s southern counteroffensive.
The intensifying push is one of Russia’s few offensive operations in months, as it tries to seize land in Ukrainian regions it claims to have already annexed.
A month of reporting by New York Times journalists found the fighting mostly stalemated and Ukraine facing an array of obstacles against a determined foe.