10:37 AM PT -- Boxing star Oleksandr Usyk has also joined in the fight ... taking up arms in his home country following Russia's invasion.
Usyk was seen with a rifle in Ukraine on Monday afternoon ... after he reportedly joined a territorial defense battalion.
Oleksandr Usyk joined the Kyiv Territorial Defense in Ukraine to defend his country from Vladimir Putin's invasion by Russia… pic.twitter.com/UUHZy0ADVe
— Michael Benson (@MichaelBensonn) February 28, 2022
The Ukranian fighter had previously posted a message to Vladimir Putin on his Instagram page over the weekend ... imploring the Russian politician to "stop this war."
Vasyl Lomachenko -- arguably the best pound-for-pound boxer on the planet -- has joined the fight in his home country, taking up arms in Ukraine to help fend off Russia's invasion.
The 34-year-old former champ and two-time Olympic gold medalist was seen carrying an M16 while dressed in fatigues near his hometown over the weekend.
In a post on his Facebook page, reps for Lomachenko posted a picture of the fighter in his gear with the caption, "The Bilgorod-Dnistrovsky Battalion of Territorial Defense is formed and armed."
Lomachenko reportedly traveled to his home country shortly after Russia invaded last week ... joining former star boxers Vitali Klitschko and Wladimir Klitschko in the fight.
"We are so proud of our boxers, our real champions in boxing and champions in this war," the president of WBC Ukraine, Mykola Kovalchuk, told ESPN. "We are proud to be Ukrainians."
Lomachenko -- who last fought in December against Richard Commey -- is just a couple months away from his next fight, which will reportedly be against George Kambosos in the beginning of the summer.
Originally Published -- 6:09 AM PT