"Keep fighting boys! Never surrender!"
That's heavyweight champion Tyson Fury addressing Vladimir Putin's Russian invasion of Ukraine ... voicing support for star boxers like Kyiv mayor Vitali Klitschko, Wladimir Klitschko, Vasyl Lomachenko and Oleksandr Usyk.
TMZ Sports talked to the 33-year-old boxing superstar about the unprovoked war ... and the "Gypsy King" even said if the fight came to the US or UK, he'd be right there, gun in hand.