Justin Bieber and Eminem. Pictures: Instagram
Justin Bieber has claimed that Eminem "doesn't understand" the new generation of rap.

The 'What Do You Mean' hitmaker has seemingly criticised the legendary rapper, after he used his track 'The Ringer' to slam some of rap's new stars including 21 Savage, Machine Gun Kelly, Iggy Azalea, Lil Pump and Lil Xan.

After posting 'The Ringer' to his Instagram story, Justin followed up with a note that read: "I just like Em's flow but don't like that he's dissing new rappers. I like the new generation of rap, he just doesn't understand it. (sic)"

Eminem had a particularly strong war of words with Machine Gun Kelly and previously revealed he dissed him a track because the young rapper accused him of hindering his career.

He explained: "The reason that I dissed him is because he got on - first he said, 'I'm the greatest rapper alive since my favourite rapper banned me from 'Shade 45,' or whatever he said, right? Like I'm trying to hinder his career. I don't give a f**k about your career. You think I actually f***in' think about you? You know how many f***in' rappers that are better than you? You're not even in the f***in' conversation.

"Now I'm in this f***in' weird thing, because I'm like, 'I gotta answer this motherf***er.' And every time I do that, it makes that person - as 'irrelevant' as people say I am in hip-hop - I make them bigger by getting into this thing, where I'm like 'I want to destroy him. But I also don't want to make him bigger.' You know what I'm saying? Because now you're a f***ing enemy' [...] I'll leave it at that. I'm not sure exactly what I'm going to do at this point right now."