LOS ANGELES, AMERICA - Pop singer Rihanna pulled out of a performance at the Grammys Sunday as police in Los Angeles confirmed they were seeking her boyfriend in connection with an allegation of domestic violence.

The 20-year-old, Barbados-born singer had been due to perform early in the show at the Staples Center before organizers abruptly announced her withdrawal just before the event.

'We have just been informed that Rihanna will not be attending the 51st Grammy Awards,' a spokeswoman said. 'We're sorry she will not be performing this evening. We have no further information.'

Earlier, a Los Angeles Police Department spokeswoman would neither confirm nor deny that Rihanna was the victim in an alleged domestic violence incident involving her boyfriend, singer-songwriter Chris Brown.

Police said a woman told police she and Brown, 19, were in a car travelling in Los Angeles's Hancock Park neighborhood early Sunday when an argument broke out. Brown allegedly stopped the vehicle and the argument escalated. According to police, the woman 'suffered visible injuries and identified Brown as her attacker.'

When police arrived, the woman was there but Brown had already left. 'He has not been arrested, but we are attempting to locate him so he can be taken into custody,' said LAPD Officer Karen Smith. -AFP