London, Feb 24 : Rihanna has hired President Obama's former Secret Service staff to protect her after being hit with death threats.

The popstar has increased security after a series of vile taunts following her first public appearance with beau Chris Brown at the Grammy Awards earlier this month.

Angry fans turned on her after she rekindled her on-off relationship with the hip hop star, who assaulted her in 2009.

The pair were spotted all over each other last week during a break in Hawaii to celebrate the Barbadian singer's 25th birthday.

While she was out on her holiday, her home was fitted with a new security system, including a fully-equipped panic room.

The `Umbrella' sitmaker decided to beef up her protection after a man was arrested for trying to break into her Pacific Palisades pad in LA.

But the intruder picked the wrong house and attempted to get into a neighbour's property.

"Death threats against Rihanna have tripled since her public appearance with Chris at the Grammy Awards," a source said.

One of the precautions being taken is to bring in two of President Obama's ex-Secret Service agents to protect her, who have been on rotation 24/7 - standing outside her hotel room and on close call at all times. (ANI)