Battlefield Replace: The entrenchments Ukraine is encountering are ‘not as sturdy,’ a military spokesman says.

THE BATTLE: Ukraine’s counteroffensive, launched in early June, aims to reclaim land in the south and east of the country. Its goal in the south is to reach the Sea of Azov and drive a wedge through Russian-occupied territory, and its main effort so far has been in the direction of the city of Melitopol. Last week, Ukrainian forces said that they had retaken the village of Robotyne, breaching the first of several tiers of formidable defenses that Russia has built in the south, and that they were moving toward another defensive line.

THE LATEST: Military analysts say that in recent days Ukrainian forces have been battling to break through the next Russian defensive line near the village of Verbove, nine miles east of Robotyne. Groups that study open-source information on the war say that Ukrainian forces have cleared some Russian entrenchments there, although it is unclear if they have retaken and secured territory in the area.

The Black Bird Group, a volunteer organization that analyzes satellite imagery and social media content from the battlefield, said on Monday that Ukrainian forces had reached Russian infantry fighting positions in the outskirts of Verbove, meaning they had made it past some anti-tank ditches and obstacles.

Oleksandr Shtupun, a spokesman for the Ukrainian Army in the south, told national television that the Russian trenches and dugouts that Kyiv’s forces were now encountering were “not as strong” as on the first line of defense. But he added that Russian minefields would complicate Ukraine’s push forward, and military analysts have suggested that Moscow has reinforced its defenses south of Robotyne with more troops.

WHY IT MATTERS: The retaking of Robotyne marked a significant moment in Ukraine’s efforts to sever Moscow’s supply lines to occupied Crimea. Its push from Robotyne east to Verbove is aimed at widening the breach that its forces have created in Russia’s layers of defenses, military analysts Michael Kofman and Rob Lee wrote in a paper published on Monday. Expanding that breach is crucial because “a narrow advance could leave its forces vulnerable to counterattacks on the flanks,” they said.

Widening and securing that gap would also allow Ukrainian forces to bring in more equipment and personnel to support their advance south. A strategic target in this push appears to be the city of Tokmak, a road-and-rail hub about 15 miles south of Robotyne.

To reach Tokmak, Ukrainian forces would have to fully break through the defenses around Verbove and then breach additional layers. This suggests a slow and exhausting fight that could take several more months, with a likelihood of mounting casualties on both sides.