Wagner chief Yevgeny Prigozhin reportedly extended the offer to Ukraine a number of times but was rejected due to a lack of trust.
"The myth of the mighty Russian army, which has haunted Europe and Germany for so long, is finally being dispelled," Ukrainian presidential advisor Mykhailo Podolyak said.
More than a thousand Russian military personnel perished on the battlefield over the weekend as their death toll continues to inch closer to the 200,000 mark.
Some of the strategic bombers near the border were involved in cruise missile attacks on Ukraine.
Arman Soldin: from Bosnia to Ukraine with a smile
A Russian soldier indicated his willingness to surrender to a Ukraine-operated drone despite fears his colleagues in the military would kill him.
Defense Secretary Lloyd Austin said the U.S. will continue to 'strengthen NATO's collective defense and deterrence.'
Russia is poised to mark another grim milestone in its war against Ukraine as the death toll of Russian soldiers inches closer to the 200,000 mark.
Russia has pulled tanks and howitzer armaments, first manufactured in the 1940s and decommissioned in the 1980s, from storage to use in its war in Ukraine.
Russian milbloggers claim the strike may have killed Ukrainian Chief Advisor Alexei Titarenko.
Russian mercenary boss Yevgeny Prigozhin complained on Wednesday that his Wagner fighters were still not getting enough shells from the defence ministry to underpin what he said was their advance in the eastern Ukrainian city of Bakhmut.
North Korean leader Kim Jong-Un has commended Russia for its victory against the Nazis in 1945 and expressed confidence in its ongoing war with Ukraine.
The Ukrainian military has revealed that members of a Russian army brigade have been caught on video fleeing from the frontlines in the heavily contested city of Bakhmut.
The head of Russia's Wagner mercenary force fighting in eastern Ukraine said on Tuesday said he had been told he and his men would be regarded as traitors if they abandoned their positions in the city of Bakhmut.
Russia's Wagner mercenary group is now accepting Nazi sympathizers to join the war in Ukraine, despite Vladimir Putin's aim to "de-Nazify" the country.
Soldiers are left in a state of "shock" and severely traumatized by shelling during the ongoing war in Ukraine.
The ongoing armed conflict between Ukraine and Russia poses a significant risk to Zaporizhzhia nuclear power plant, a U.N. watchdog claimed.
A video recorded by Ukraine's volunteer Belarusian fighters showed the intense operation to repel Russian troops from the trenches near Bakhmut.
Russia is now scrambling to accumulate missiles ahead of Ukraine's anticipated counteroffensive.
"If some young men in Russia, just because of this game, happen to think for a couple of seconds what is going on in Ukraine then it's worth it," said Antero Mukka, the editor-in-chief of Helsingin Sanomat.
Wagner chief Yevgeny Prigozhin said Russia's threats of using nuclear weapons in response to the alleged Ukrainian drone strikes make Moscow "look like clowns."
The United States dismissed Russia's allegation on Thursday that Washington was behind what it said was a drone attack on the Kremlin, saying Moscow's assertion was a lie.