Thousands Flee as Russian Forces Advance in Eastern Ukraine

Thousands of civilians are fleeing eastern Ukraine as Russian forces intensify their spring-summer offensive against the “Fortress Belt” — a string of fortified cities in the Donetsk region including Sloviansk, Kramatorsk, Kostiantynivka, and Druzhkivka. The escalating hostilities have triggered a humanitarian crisis, with Ukrainian authorities ordering the forced evacuation of families with children and the relocation of key industrial infrastructure from the threatened cities.

The Fortress Belt Under Siege

The four cities running north to south along the H-20 highway — Sloviansk, Kramatorsk, Kostiantynivka, and Druzhkivka — have formed Ukraine’s main defensive line in Donetsk for years. According to the Institute for the Study of War, Russian forces launched their planned spring-summer offensive in 2026 from two directions: the Lyman direction northeast of Sloviansk and the Pokrovsk direction. The main pressure is focused on the Lyman axis, which opens the way to Sloviansk and Kramatorsk.

Russia currently controls approximately 70% of Donetsk region. If the Fortress Belt falls, Moscow would achieve a key war aim — virtually complete control of the Donetsk region.

Mass Civilian Evacuation

The humanitarian toll is mounting rapidly. On June 9, Donetsk Regional Military Administration Head Vadym Filashkin expanded the forced evacuation zone for families with children to include specific streets in Sloviansk, Kramatorsk, and Bilenkyi, as well as the entire territories of Pryvillia and Malotaranivka, as reported by LIGA.net.

“The zone of forced evacuation of families with children has been expanded once again in Donetsk region,” Filashkin said, “this time including some streets of the largest cities in the region that are under Ukrainian control.”

This follows an earlier order in March 2026, when Filashkin signed a directive for the forced evacuation of children from over 30 of the most dangerous streets in Sloviansk. “Saving lives is the most important thing,” he said at the time, according to UNN. “Especially the lives and health of children who are unable to make decisions and leave on their own.”

Industrial Heartland on the Move

In a significant development on June 14, Kyiv ordered the evacuation of key industrial enterprises and their workers from Kramatorsk and Druzhkivka. The Eastern Herald reported that the Russian Defense Ministry framed the evacuation not as the result of a strike, but of Russian “successful actions and advance.”

The evacuation is not improvised. Ukraine began preliminary work on a project called “New Kramatorsk” as early as 2022, transplanting the city’s metalworking and machine-tool factories to Perechyn in the Zakarpattia region of far-western Ukraine. More than 3,500 skilled workers had already moved west. The Economist described the mood inside Kramatorsk as “extremely alarming,” with “little optimism” among those who remained.

Relentless Bombardment

Russian forces are targeting the region with guided aerial bombs (KABs) and Geran-2 attack drones. On June 1, an electrical substation in Kramatorsk was struck, leaving the area without power for several days. Journalist Volodymyr Zharky reported via 112.ua that “the enemy is attacking Kramatorsk, Sloviansk, and Druzhkivka with every weapon in its arsenal.”

Conditions in Kostiantynivka and Oleksievo-Druzhkivka have become so severe that evacuation by car is no longer feasible. Residents must now flee on foot toward Druzhkivka and Kondrativka, where volunteers are waiting to assist them. By mid-June, the front line was just 14 kilometers from Kramatorsk.

Tactical Gains and Strategic Uncertainty

Russia’s Zapad Group of Forces reached the northwestern outskirts of Lyman and established control over several districts of the city, according to the Russian Defense Ministry. However, the ISW assessed that Russia’s Western Grouping likely lacks the combat power to simultaneously advance on Sloviansk while holding the line in Kupyansk and Borova, where Ukrainian counterattacks have been forcing Russian units to choose between defending and attacking.

ISW assessed as recently as June 10 that Russian forces are likely to make tactical gains in Kostiantynivka this summer, while cautioning they are unlikely to achieve full operational breakthroughs against the broader Fortress Belt in 2026 — a distinction Kyiv’s industrial planners appear no longer willing to bet on.

What to Watch For

The coming weeks will be critical. The evacuation of civilians and industrial infrastructure signals that Ukrainian military planners are preparing for the possible fall of these cities. The “New Kramatorsk” project represents a strategic hedge — Ukraine is preserving its industrial base by moving it west. Meanwhile, Ukrainian strikes on Russian logistics across the Kerch Strait, reported by ISW on June 21, may be aimed at degrading Russia’s ability to sustain a prolonged offensive.

The question that remains unanswered is how many civilians can be evacuated in time, and whether Ukraine’s defensive lines can hold through the summer.