Russian forces have spent months trying to capture the city as part of their offensive in eastern Ukraine, and the area has seen some of the bloodiest ground fighting of the war.

The discovery came shortly after Ukraine marked the first anniversary of President Vladimir Putin’s invasion, which initially sought to topple the Ukrainian government and capture the capital Kyiv.

The short encounter came as relations between Washington and Moscow have plummeted over Russia’s war with Ukraine and tensions have soared amid a myriad of disagreements, complaints and recriminations.

Analysts say the fall of Bakhmut would be a blow for Ukraine and offer tactical advantages to Russia, but would not prove decisive to the war’s outcome.

The attacks raised questions about Russian defense capabilities more than a year after the country’s full-scale invasion of neighboring Ukraine.