The head of Russia's Wagner mercenary group said in a rare interview made public on Friday that Russian forces must capture the strategic city of Bakhmut to proceed with their campaign but faced fierce resistance from Ukrainian defenders. Yevgeny Prigozhin, interviewed by a Russian military correspondent, said Russia had to establish clear goals in its nearly year-old campaign: firmly establish its presence in eastern Ukraine or push forward to capture more of the country. Moscow invaded Ukraine on Feb. 24, eight years after it annexed the Crimean peninsula and its proxies took large swaths of territory in eastern Ukraine, styling them as the "people's republics" in the Donetsk and Luhansk regions. Prigozhin, an entrepreneur and restaurateur, has attracted attention as fighting raged in this campaign. He has criticized Russia's military leadership and certain officials. Wagner troops have played a large role, particularly last month in capturing the town of Soledar - outside Bakhmut, which has endured months of combat and bombardment and is known to both sides as the "meat grinder". "Bakhmut is needed so our troops can operate comfortably," Prigozhin said. "Why is it called the meat grinder? Because the Ukrainian army is sending more and more and more units." "It is probably too early to say that we are close. There are many roads out and fewer roads in. Ukrainian troops are well trained ... and like any large city it is impossible to capture it from head-on. We are managing very well. "First we have to quietly take Artyomovsk and then we can say loud and clear that we have taken it," he added, referring to Bakhmut by the Soviet-era name used by Moscow. He said the fighting to capture Soledar - undertaken after failures in taking Bakhmut - was comparable to the six months of battles needed for the Soviet army to secure Stalingrad. Military analyst Oleh Zhdanov said the situation around Bakhmut probably remained the most difficult sector faced by Ukraine's forces as Russia deploys more and more conscripts. "The area south of Bakhmut is a very difficult sector," Zhdanov said in an online interview. "And the city itself remains the hottest spot on the front at this time."