In this photo released by TMZ.com, R&B singer Rihanna is shown shortly after her alleged assault February 8, 2009. R&B star Chris Brown, who was arrested last weekend on suspicion of attacking a woman widely believed to be the pop star Rihanna, said on Sunday he was "sorry and saddened" about the incident, and was seeking counseling. [Agencies]

Chart-topping Rihanna, speaking for the first time since being brutally beaten before the Grammy Awards, said Friday she is "strong" and "doing well."

But the Jay-Z protégé, who spent her 21st birthday in private Friday, would not discuss boyfriend Chris Brown's role in the vicious Feb. 8 attack.

"At the request of the authorities, Rihanna is not commenting about the incident involving Chris Brown," her two-sentence statement read. "She wants to assure her fans that she remains strong, is doing well and deeply appreciates the outpouring of support she has received during this difficult time."

Rihanna's remarks came after her father ripped Los Angeles police over the leak of a graphic photo showing her bruised and battered face.

"Sloppy work on their part," Ronald Fenty told People magazine, adding that his daughter had no plans for a birthday celebration as she recovered from the assault.

The "Umbrella" singer, who has remained in seclusion since the incident, was spotted in Los Angeles Thursday night. She had been with family in her native Barbados. Friends there took out a newspaper ad Friday wishing her a happy birthday.

The shocking picture showed Rihanna - her eyes closed tight - with deep bruises on her forehead, black marks around her eyes and dried blood at the corner of her mouth.

Her father, while upset with the LAPD, said the leak of the photo to celebrity Web site TMZ.com did illustrate the brutality inflicted on his daughter.

"It's good and it's bad to see the picture, because there's other people who were thinking differently, that [her injuries] may not be that bad," Fenty told Us Weekly magazine.

Brown, 19, whose hits include "Run It!," missed his scheduled Grammys appearance after his arrest on suspicion of making criminal threats to a woman - although the LAPD never confirmed it was Rihanna.

The pair had attended a pre-Grammy party honoring music mogul Clive Davis prior to their reported altercation. Brown remains free on $50,000 bail.

After the photo was posted Thursday night on TMZ.com, the LAPD called its release a serious violation that could lead to departmental firings.

TMZ declined comment on a blog report that it had paid $62,500 to "a law enforcement insider" for the picture.