The whereabouts of the head of Russian private military firm Wagner Group is not yet known after he led a short-lived mutiny with his mercenary forces.

Meanwhile, the Russian defense ministry has released a video that purportedly shows the defense minister visiting the advanced command post of Russian troops involved in the conflict with Ukraine.

Wagner founder Yevgeny Prigozhin staged an armed mutiny against the ministry amid a deepening rift between the two sides.

Prigozhin's troops were advancing toward the capital Moscow when he suddenly turned them around. He also pulled out from the Russian military headquarters he had captured in the southern region.

Kremlin spokesperson Dmitry Peskov said on Saturday night that Prigozhin would go to Belarus. But Prigozhin has yet to post any messages on social media.

On Sunday, Russian online media quoted Prigozhin's press service as saying that he sends his regards to everyone and will answer questions when he is back on normal communication.

Peskov said on Saturday that the criminal case against Prigozhin will be dropped, but some Russian media reports on Monday quoted sources close to prosecutors as saying an investigation into the case is still ongoing.

Meanwhile, the Russian defense ministry announced on Monday that ministry chief Sergei Shoigu visited the frontline command post of what Moscow calls special military operations in Ukraine. It released video footage purportedly showing Shoigu being briefed by the commander there.

It was the first reporting on Shoigu since the mutiny started. Prigozhin has been singling him out in his criticism of Russian military operations in Ukraine and was calling for his dismissal.

Observers say the footage may be directed to Russian troops involved in the conflict to show that the defense minister is in control.

The Russian presidential office also stressed that the situation in Russia would not affect military operations in Ukraine.

Ukrainian deputy defense minister Hanna Maliar said in a social media post on Monday that Ukrainian forces had achieved tactical successes in the east over the past week.

And Britain's latest defense intelligence update on Ukraine states that "As part of its broader counter-offensive, Ukraine has gained impetus in the assaults around Bakhmut in Donetsk region."

Observers say Ukrainian forces are apparently taking advantage of the turmoil in Russia to give momentum to its counteroffensive.