Boxing legends Wladimir and Vitali Klitschko have pledged to defend their country from foreign invaders and have promised to keep Ukraine free or die trying.

The former world champions are currently in Kyiv, where they have taken up arms against the Russian and Belarusian forces who invaded last week.

Wladimir is considered to be one of the greatest heavyweight champions of all time, going an incredible 64-5. The 6'7 Vitali retired in 2013 and finished his career with an incredible 45-2 record.

Vitali Klitschko, who is now the mayor of Kyiv, feels a special responsibility to lead by example.

He told CNN, as per The Mirror: "We're ready to die for our home county and for our families, because it's our home.

"We're not interested in how strong the Russian army is, we're ready to fight."

The older Klitschko brother spoke about his pride that so many compatriots have risked their lives and stayed to fight for their country's freedom.

"We have stayed in front of one of the strongest armies in the world.

"We are defending our families, our city, our country and our future.

"There is huge patriotic movement right now. Old people, can you imagine? Doctors, actors, many professions that never had any expectation to fight, to keep weapons, they're ready to fight, that's amazing."

Current heavyweight champion Oleksandr Usyk has also flown back to Ukraine and is currently protecting an underground bunker in Kyiv where civilians are taking shelter.

Usyk has joined the Kyiv Territorial Defence Force and has pledged to protect his country by any means necessary.