7:57 PM ET

With his country at war with Russia, Oleksandr Usyk was preparing for a second fight against Anthony Joshua.

The much anticipated bout has been delayed.

Eddie Hearn, Matchroom Boxing's president, said that they don't want the obligation of a rematch to go away.

A 35-year-old man joined a territorial defense battalion after he returned to Ukraine. Usyk dominated Joshua in September to win the title, and now he wants to face the Englishman again.

The rematch clause guarantees another fight between Joshua and Usyk with financial terms agreed to. Usyk-Joshua 2 was supposed to happen in May or June, but with the situation in Ukraine, it is not certain when the fight will happen.

Usyk told CNN that he doesn't know when he's going to return to the ring.

Usyk, who has three children, is concerned about what is to come, but also committed.

He said that he doesn't want to shoot, but if they kill him, he will have no choice.

If there is an extended delay, it is possible that he will book an interim fight for Joshua.

It is a very unique, personal, emotional situation and I don't think we can comprehend what is going on there.

We don't want the obligation of a rematch to go away, so we will wait as long as Oleksandr Usyk needs.

Usyk's friend and fellow Olympic gold medal winner, Vasiliy Lomachenko, joined a defense battalion, throwing a potential June 5 clash with George Kambosos into question. The mayor of Kiev, Vitali, and his brother, Wladimir, took up arms as well.

The bombing around is crazy, but there is no fear. How could this happen in the 21st century?

When there is an air-raid alarm, we hide. It helps me to help others who are frightened.