Heavyweight champion Oleksandr Usyk says his “country and honour” are more important than any fight in the ring as he prepares to defend Ukraine’s capital Kyiv against invading Russian forces.

“There is no fear, absolutely no fear,” he told CNN.

“There’s just bafflement – how could this be in the 21st century?”

Usyk, who was speaking via video call and an interpreter from a basement in Kyiv, said he did not know if there was any chance of him fulfilling a planned May rematch with Joshua.

“I really don’t know when I’m going to be stepping back in the ring,” he said.

“My country and my honour are more important to me than a championship belt.”

Usyk has previously called on the Russian people to resist the war and for the country’s president Vladimir Putin to engage in peace talks without pre-conditions or claims to Ukrainian territory.

He is one of several former and current Ukrainian boxers who have come to the defence of their homeland.

Vasiliy Lomachenko, a three-weight world champion who has wins over Britons Luke Campbell and Anthony Crolla on his professional record as well as two Olympic golds from his time as an amateur, has also taken up arms.

Brothers Vitali and Wladimir Klitschko, both former heavyweight world champions, are also in Kyiv.

Vitali, 50, has been mayor of the city since 2014 while Wladimir, 45, joined the city’s military reserve last month.

“In Kyiv there is a huge movement for civil defence,” Vitali told BBC News. “Lines hours long full of young people ready to take weapons and be part of the civil defence in our city.

“We are fighting for democracy and our choice,” added Wladimir. “Terrible events happened in the past six days: men, women and children dying, but I am proud of our men and women who are ready to defend our country for our children.”