WBC heavyweight champion Deontay Wilder has issued an angry response to Anthony Joshua's threat that he is ready to "ram his jab down his throat".

The American and London fighter Joshua are destined for a unification bout in 2018 and have wasted little time beginning a war of words.

The reigning IBF and WBA champion Joshua told Sky News he believes it is inevitable he will have to face both David Haye and Wilder, who he has nicknamed 'Beyonce'.

And though Wilder has ignored the insult, he has taken aim at the language used by Joshua. "Bro, like what the f**k Anthony Joshua? You're going to soon be ramming your jab down my throat?! To be honest, this don't sound too good unless it's some next level ish," he wrote on Instagram.

"I guess I'll have to son you and teach you how a champion supposed to talk — so when they hear you, they shall also feel you. Next time I'd rather hear how you gonna knock my ass out. Make me smile."

Joshua and Wilder will box on consecutive weekends before the end of the year, with the Briton taking on Kubrat Pulev in Cardiff on 28 October before his rival faces Bermane Stiverne in New York on 4 November.

Stiverne was installed as Wilder's new opponent after Luis Ortiz failed a drugs test, having tested positive for two diuretics. The Cuban however remains the mandatory challenger for Joshua's WBA crown, a status that remains intact.

In order to set up a unification fight with Wilder or WBO champion Joseph Parker, Joshua must fulfil the mandatory challenge and is awaiting clarification over whether Ortiz's positive negative affects that position.

"I don't know what's happening," the Olympic gold medallist's promoter, Eddie Hearn, said, according to The Times. "The WBC say they won't sanction the fight, Ortiz's team say they are about to be cleared.

"The WBA have to rule on their position, they might have to install him as the mandatory. At the moment he is the mandatory, then he went to fight Wilder and the WBA said they would still make him mandatory."