Xu Can has slammed British boxer Josh Warrington as a "30-year-old baby" as tensions flare between the two featherweights over their on-off bout.

"Remember this, Warrington. I dare to fight with you anytime, anywhere in this world. Do you dare do the same?" said China's World Boxing Association champion (18-2, 3 KOs) in a video message posted on Weibo on Thursday.

Fans have been waiting for the title-unification bout between Xu and the unbeaten International Boxing Federation champ Warrington (30-0, 7 KOs) since 2019. The fight was unable to be staged throughout 2020 due to the COVID-19 pandemic.

Warrington and Xu were reportedly close to finalizing a deal for a February showdown in the Englishman's hometown of Leeds, however the fight has been postponed again as the pandemic rages on and with international travel restrictions proving problematic.

Warrington ignited a war of words when he told media this week that he was "close to shedding tears" after Xu pulled out of the bout — a decision which led some fans on Chinese social media to question Xu's courage.

However, China's WBA champ had a different take on the story.

"My title-unification bout was once again postponed. Anyone who watches the news of the British COVID-19 pandemic situation would say to me: 'In February? To have a fight in the UK? Are you crazy?'" Xu added in the video.

"Calling me a coward who runs away from a fight? Let's see who is the real coward. The UK is still at a critical time in the pandemic, and the nation is still under lockdown. We invited Warrington many times to China. Or we can fight in a third nation.

"But he dared not to and he said he only can fight in his hometown in the UK...I'm not afraid of fighting in the UK. Now I wish to fight with you in your hometown. So please shut your mouth and do your training. And most importantly, protect your jaw. Save it for me. That's mine."

Xu, aka 'The Monster', became China's first WBA champ when he beat Puerto Rico's Jesus Rojas via unanimous decision in Houston, Texas, in January 2019.

Warrington, aka 'The Leeds Warrior', is also preparing his best for the fight.

"A lot of people don't know that this fight has been on the cards for a long, long time. We had more or less been preparing for this fight since when I signed back up with Matchroom. That was the one we wanted," Warrington told Sky Sports News.

"I've got the artwork for the poster, all the game-plan has been about Xu, all the sparring partners have been tailored to his traits. At night time, I'm visualizing Xu. My team is studying Xu, we've got loads of data on him."