Former heavyweight champion Vitali Klitschko plans to fight for Ukraine along with brother

Former heavyweight champion Vitali Klitschko, the mayor of Ukraine's capital, Kyiv, plans to take up arms to defend against Russia's invasion, which began in the early hours Thursday.

"It's already a bloody war," Klitschko, a Hall of Fame boxer, said Thursday on ITV's "Good Morning Britain." "... I don't have another choice. I have to do that. I would fight."

Klitschko, 50, became mayor in 2014, along with head of the Kyiv City State Administration. That same year, Klitschko was a leading figure in the protests against closer ties with Russia. And now, as Kyiv is under siege, along with other regions, Klitschko is again at the forefront defending Ukraine along with his brother, fellow former heavyweight champion Wladimir Klitschko -- who is also a Hall of Famer.

Wladimir, 45, enlisted in Ukraine's reserve army in Kyiv earlier this month as the country braced for an attack.

"Now, the Russian president [Vladimir Putin] is using war rhetoric ... he makes it clear that he wants to destroy the Ukrainian state and the sovereignty of its people," Wladimir Klitschko wrote on Linkedin on Thursday. "Words are followed by missiles and tanks. Destruction and death come upon us. ... We will defend ourselves with all our might and fight for freedom and democracy."

Active boxers from Ukraine are also being impacted by the invasion. Vasiliy Lomachenko, a two-time Olympic gold medalist and three-division champion, fled Ukraine for Greece, according to Sports Illustrated. 

Heavyweight champion Oleksandr Usyk, who defeated Anthony Joshua in September, was in London earlier this week for a meeting related to an upcoming boxing video game but was back in Ukraine on Thursday.

"Some wrote to me that I ran away; I didn't, I was at work but I'm back, I'm home," Usyk said in an Instagram video in comments translated from Russian. "Friends, we have to unite because it's a hard time right now and I'm really emotional and worry about my country, and our people. Friends, we have to stop this war; all of us together.

And then there's former 140-pound champion Viktor Postol, who fights Saturday in Las Vegas against Gary Antuanne Russell.

"The situation in Ukraine escalated a lot last couple of days, it's hard not to think about it, but I try to focus on the fight and not for the news," Postol said at Thursday's news conference to promote the Showtime fight. "My family is there in the middle of everything. But I am going to have my people there and my family is safe."