Russia appears to be escalating its attacks against Kyiv.
Ukrainian officials say several people were killed over the weekend trying to flee the beleaguered city.
The Klitschko brothers are in the biggest fight of their lives defending Ukraine's capital from Russia.
Vitali Klitschko was an undefeated WBC heavyweight champion and is the mayor of Kyiv.
"Were ready to fight, not just for our city, not just for our country," Vitali Klitschko said. "We're fighting for exactly the same values for the same principles. It's this world, can touch anyone, everyone, everyone in the European Union, in Europe and can touch everyone in the world.”
For Vitali's brother, former heavyweight boxing champion Wladimir Klitschko says the whole country is highly motivated to stop the war.
"There is nothing that is possibly can break the will of our women and men," Wladimir Klitschko said. "We all stand together and we're highly motivated to defend our country because this is our home."
The Klitschko brothers dominated the boxing world between 1999 and 2015.
Now they are willing to sacrifice their lives to protect their country.
"This is our home, and there is no other way that we're going to leave and why, because this is our home. So, we will defend the country until [the] last drop of the blood," Wladimir Klitschko said.