Madonna's security worries

Madonna is increasing her personal security after receiving a series of threatening letters.The 48-year-old singer, who is married to film director Guy Ritchie, has reportedly had a number of "highly disturbing and threatening" letters delivered to her New York home in the past four weeks.It is believed the letters could be coming from angry animal rights campaigners who are furious with Madonna for wearing a £35,000 coat made out of chinchilla fur to a recent glitzy party.The pop superstar - who splits her time between her homes in the US and the UK - has now beefed up her security on the advice of her management team.A source said: "Madonna has been receiving some really disturbing and threatening mail. Obviously, she feels very scared and has had lengthy conversations with the police about it. Madonna's people have been growing increasingly concerned about her safety and have been left with no option but to step up her security."