Yevgeny Prigozhin, founder of Russia's Wagner mercenary group which is fighting in the battle of Bakhmut, set out in detail on Saturday why he thought its capture would be significant.
"The cherry on the cake is the system of Soledar and Bakhmut mines, which is actually a network of underground cities.
His comments were a reference to vast salt and other mines in the area which contain more than 100 miles of tunnels and a vast underground room which has hosted football matches and classical music concerts in more peaceful times.
Prigozhin, who is sanctioned in the West, cited other advantages of taking Bakhmut, calling it "a serious logistics centre" with unique defensive fortifications.
Bakhmut, which Russia calls Artyomovsk, is the focus of the most intense fighting in Ukraine, and Prigozhin made his comments as another Telegram channel associated with Wagner claimed Russia had captured a strategically-important settlement on Bakhmut's outskirts.