Amanda Bynes tweets racist remark about Rihanna and says Chris Brown

Amanda Bynes tued her anger toward Rhianna Sunday, posting racist and offensive remarks about the singer.

The embattled 27-year-old briefly posted a number of tweets about Rihanna, 25, before deleting the comments.

The tirade began with Amanda writing, '@rihanna you look so ugly tryin (sic) to be white', followed within minutes by a message blaming the singer for being assaulted by ex-boyfriend Chris Brown.

Within two minutes the troubled Disney star had deleted the first post.

Then just a few moments later, she attacked the star again with a reference to Brown's assault on her in 2009, claiming the singer did so because Rihanna was unattractive.

'Chris Brown beat you because you're not pretty enough,' Amanda tweeted.

Friends no more: Amanda has met Rihanna before, seen here together in 2006, but she continued to rant about the singer making numerous remarks then deleting them off her Twitter account

Twitter war: Amanda posted numerous offensive comments about the singer's appearance, race and being a victim of domestic violence before deleting them

The actress then retweeted a post by Rihanna: 'Look who came to see me!! My lover Stella McCartney!!!' to which Amanda responded: ''No one wants to be your lover so you call everyone and their mother that I almost named my new dog Rihanna.'

Rihanna, who is known for her own feisty temper on Twitter, appeared to address the remarks within minutes of their posting.

Firing back: Not taking it lying down Rihanna made reference to the actress' alleged drug problems

'Ya see what happens when they cancel Intervention?,' the We Found Love singer wrote.

Amanda retued fire accusing the 25-year-old of doing drugs.

'Unlike ur fugly faced self I don't do drugs! U need the intervention dog! I met ur ugly face in person! U aren't pretty u know it! (sic)'

In rhyme: Amanda even tried to rap a catty comment at the Battleship star

Speculation persists if Amanda's unrequited love for Rihanna's rumoured ex-boyfriend and collaborator, rapper Drake, sparked the Twitter attack.

Amanda's online infatuation with the musician has been well-documented. She famously tweeted in March she wanted Drake to 'murder my vagina'.

This is not the first time Amanda has made racist remarks on the micro-blog.

The star previously posted vitriolic rants about an editor of a woman's magazine that used old photographs of her; she was also tangled in controversy after making comments about a man who was photographed with her in her apartment, identified by InTouch magazine as a romantic interest.

Writing to blogger Perez Hilton Amanda fumed: 'The only thing sadder than your ugly face still writing stories about me is the fact that you think I'd even step foot in a room with that ugly faced black man.'

Amanda could be heard making similar remarks about a photographer outside her New York apartment on Saturday.

As she entered the building a paparazzo from X17, Tyrone Jackson, reached up tried to remove the scarf that was covering her face.

A video obtained by TMZ shows Amanda repeatedly telling Jackson: 'You can't touch me.'

She then asks: 'Is it the ugly black man? There's another ugly black man.'

The photographer then repeated the comment and asked if the 27-year-old was racist, a claim which she denied.

'There's an ugly white one. It's not racist,' she is heard saying.

Recent reports suggest Amanda's mental well-being has become of conce to her parents, who are believed to be seeking  conservatorship over their daughter to force her into to psychiatric care, according to RadarOnline.

Amanda's behaviour has been chronicled intensely since she left Califoia - where she was charged with DUI and other driving offenses - and moved to New York.

She recently attempted to change her appearance, piercing her cheeks, shaving off her hair and wearing wigs, all the while tweeting photos of her transformation.

She was assessed at a hospital Thursday evening following an arrest for marijuana possession.

The star spent a night in jail and then appeared in court on Friday moing for her arraignment, where she denied any wrongdoing.

Blame game: Amanda, referring to when ex-boyfriend Chris Brown assaulted the singer in 2009, claimed the rapper did so because Rihanna was unattractive

Amanda was arrested after staff at her apartment building called police alleging she had been behaving erratically and smoking marijuana.

When police arrived at the 36th floor apartment the star allegedly threw a glass bong out the window on to the street below.

She was charged with reckless endangerment, unlawful possession of marijuana  and attempted tampering with evidence.

Amanda has since accused an arresting officer of sexual harassment, claiming he 'slapped (her) vagina.'

A spokesperson for the NYPD has confirmed to MailOnline an inteal investigation is ongoing. 

Amanda is due back in court July 9 to answer the latest charges.

Bizarre behavior: The actress was arrested Thursday night after staff at her apartment building called police alleging she had been behaving erratically and smoking marijuana