President Trump and President Vladimir V. Putin both claimed that Ukrainian forces were surrounded. Ukraine’s top military commander vowed to “hold the line.”

Ukrainian forces are under intense pressure in Russia's Kursk region, where they grabbed a chunk of land last August and have held on to it through more than seven months of fierce fighting.

Sudzha, with a reported population of about 5,000 people before the offensive, was the biggest town seized by Kyiv's forces last year as part of their surprise cross-border offensive. The Russian army,