The surprise attack seeks to reverse Ukraine’s decreasing hold of the region. Since Kyiv’s forces gained partial control of Kursk following a daring cross-border assault last August, Russian troops, aided by North Korean soldiers, have halved the territory held by Ukraine, albeit while suffering thousands of casualties.

President Volodymyr Zelenskyy says he will urge allies to boost Ukraine’s air defenses at a meeting this week in Germany, while both sides said Kyiv’s forces pressed new attacks Sunday in Russia’s Kursk region.

Russia may be close to sharing advanced satellite technology with North Korea after the isolated nation supplied troops to help bolster Moscow’s war in Ukraine, United States Secretary of State Antony Blinken warned Monday.

Pyongyang has provided Moscow with more than 10,000 soldiers, artillery, and ammunition during Russia’s war as the two sides have deepened their partnership.