Nas and Kelis. Picture: Bang Showbiz/AP

Nas has accused Kelis of making "physical violent attacks" on him after she alleged that she was subjected to "mental and physical abuse" during their four-year marriage.

The 'World Is Yours' rapper has accused the 'Milkshake' singer of making "physical violent attacks" on him earlier this year and says their nine-year-old son Knight even "wonders why she treats him the way she does".

He wrote on Instagram: "After 10 years of keeping my silence during a decade of dealing with very hostile behavior and verbal abuse and even your stepfather holding you back from one of your physical violent Attacks on me right outside your house THIS YEAR while trying to pick up our son while he watched from the window, it was my weekend and you denied me that because your parents were in town. I just went home. This has been my life for my son's entire life. Even our son wonders why you treat me the way you do? (sic)"

Kelis had previously accused Nas of "abuse" during their marriage and opened up about the "really dark" marital problems they had gone through.

She said: "It was really dark. There was a lot of drinking. There was a lot of mental and physical abuse. I probably would have stayed longer had I not been pregnant [with Knight] because I really did love him and because we were married. We weren't dating, we were married. Like, this was my person ... I've waited nine years to say anything. I have never talked about this man, ever. The amount of airing out that I could do, and I've chosen not to. Our kids will find out. They're finding out now. I've never painted myself as a saint. Did he hit me? Mmhm. Did I hit him back? Mmhm."