Russia has recaptured a few villages in its western borderlands that Ukraine invaded over the summer, threatening Kyiv’s hold on territory it views as crucial leverage for pushing Moscow toward negotiations to end the war.

In recent days, Russian troops have intensified efforts to dislodge Ukrainian forces from the bulge of territory they seized in Russia’s western Kursk region, launching several assaults spearheaded by armored vehicles. Battlefield maps compiled by independent groups using satellite images and combat footage indicate that Russian forces have driven a wedge into the western edge of the Ukrainian bulge, recapturing at least three villages.

“In general, the situation in Kursk is not so good,” DeepState, a group with close ties to the Ukrainian army that analyzes combat footage, said Sunday. Ukrainian forces “are taking stabilization measures, but it is extremely difficult to reclaim what has been lost.”

Emil Kastehelmi, a military analyst for the Finland-based Black Bird Group, said that some elements of Russian units had “managed to advance relatively far into the Ukrainian rear, which caused issues and losses for Ukraine.”

To be sure, Ukraine still holds roughly 300 square miles of Russian territory, according to the Black Bird Group, down from about 400 square miles in the first weeks of its cross-border assault in the Kursk region, which was launched in early August.

The offensive had two primary objectives: to force the Kremlin to divert troops from other parts of the front to respond to the attack, thereby easing pressure on Ukrainian forces; and to capture territory that Moscow will seek to reclaim, potentially forcing it to come to the negotiating table.

While the first goal appears to have failed so far — with the Kremlin mainly deploying reserves from within Russia while intensifying assaults in eastern Ukraine — officials in Kyiv have clung to the second goal as part of their so-called “victory plan” to push Russia into peace negotiations.

The Kursk offensive is one of “the stages to end the war,” Ukrainian President Volodymyr Zelenskyy said during a news conference in late August.

But each Russian advance in the Kursk region risks diminishing the value of this bargaining chip.

“The Russian counterattacks are constantly reducing the political significance of the Ukrainian-controlled area in Kursk,” Kastehelmi said. “If the current trend continues, the Ukrainians may need to reconsider their presence in the area and the future of the whole operation.”

Ukraine first invaded the Kursk region on Aug. 6, swiftly capturing dozens of villages and settlements, including the small town of Sudzha. It took Russia several weeks to stabilize the situation by sending in reinforcements to halt the Ukrainian advance. Military analysts and U.S. officials said Russia’s response was initially slow and scattered as the Kremlin determined which military and security forces should lead the counterattacks.

Ukrainian officials and soldiers have generally been tight-lipped about the situation in the Kursk region in order to preserve operational security. But Zelenskyy acknowledged the intense fighting in a message posted on social media Monday.