A woman claiming to be Prince's half-sister has come forward saying she is entitled to part of the late pop star's multimillion-dollar estate, legal documents show.

The life of the singer Prince, who has died at the age of 57, is being marked with purple-coloured tributes. Buildings, newspaper front pages and websites across the US and beyond change colour in his honour.

US pop star Prince, 57, was found unresponsive at his Minnesota home and was later declared dead, US media reports say.