(NEXSTAR) — Vitali Klitschko, the mayor of Ukraine’s capitol city of Kyiv, has said he would fight in the streets amid Russia’s invasion of his country, if need be.  

“I don’t have another choice,” he told a reporter with ITV’s “Good Morning Britain” in an interview on Thursday. “I would have to do that … I will be fighting.”

Klitschko, also a member of the International Boxing Hall of Fame, described the unfolding invasion in Ukraine as a “nightmare.”

“We stand in front of one of the biggest and strongest armies in the world, but we have to defend our families, defend our country, our cities, and we (don’t) have another choice,” he said.

Klitschko’s brother, Wladimir Klitschko, has already vowed to fight for Ukraine, having enlisted in the Ukrainian reserve army earlier this month, Reuters reported. In a post shared via LinkedIn, Wladimir — also a member of the International Boxing Hall of Fame — urged the international community to support Ukraine’s efforts and “stop the march of imperialism.”

“After all, whose turn will it be after Ukraine?” he asked.

The Klitschko brothers’ remarks come after Russia launched a full-scale invasion of Ukraine in what NATO chief Jens Stoltenberg called “a brutal act of war.” Ukrainian President Volodymyr Zelenskyy said more than 130 people died on the first day of the attack, with hundreds more injured, The Hill reported.

Klitschko said the city of Kyiv, along with Ukraine’s military, was making it a “main priority” to defend critical infrastructure and maintain utilities for residents. The mayor added that many of those residents were also training in civil defense to become “soldiers ready to defend our city.”

“Ukraine was always a peaceful country, peaceful people,” he said in the “Good Morning Britain” segment. “But right now we have to take weapons and fight.”