Russian mercenary leader Yevgeny Prigozhin decried the loss to Ukrainian forces of a village near Bakhmut and said tactics used by regular Russian forces would lead to more setbacks within two weeks.
Prigozhin made his comments on Monday as a top Russian-backed official in occupied Donetsk region described the military situation around Bakhmut as difficult.
Prigozhin's private Wagner militia captured virtually all of Bakhmut in Ukraine's east last month after the longest battle of the war and handed its positions there to regular Russian troops.
Since then, Ukraine has continued to attack areas north and south of the city.
"Now part of the settlement of Berkhivka has already been lost, the troops are quietly running away. Disgrace!" Prigozhin said in an audio message published by his press service.
Berkhivka lies about 3 km (2 miles) northwest of Bakhmut, and Wagner claimed its capture on Feb. 24.
In an interview posted on Telegram later on Monday, Prigozhin said Russia's defence ministry was duping the public and Kremlin leaders with its tactics.
He said Ukrainian movements in the area "can happen much faster than our advances".
"The Ministry of Defence's tactics are malicious and deceptive," he said in the online interview.
"The Ministry of Defence's main goal is to pretend that everything is ok and that we are advancing. In reality, what is happening now ... will result in significant tactical defeats in two weeks' time."
Denis Pushilin, the top Moscow-backed official in the Russian-occupied part of Donetsk region, which includes Bakhmut, told Russian state television the situation on the city's flanks was "under control" but "very difficult".
Prigozhin has urged Defence Minister Sergei Shoigu and the chief of the general staff, Valery Gerasimov, to come to the front to rally the troops.
"Come on, you can do it!" he said in his message. "And if you can't, you'll die heroes."
Prigozhin has waged a public feud with Shoigu and Gerasimov for months, accusing them of failing to provide sufficient ammunition and support for Wagner in the field, and so causing it to suffer needlessly heavy losses.
In recent days, Prigozhin has further escalated the row, accusing regular forces under the command of the defence ministry of mining roads out of Bakhmut used by Wagner units.
