LOS ANGELES (Reuters) - Whitney Houston, whose soaring voice lifted her to the top of the pop music world but whose personal decline was fueled by years of drug use, died on Saturday afternoon in a Beverly Hills hotel room. She was 48.

The pop superstar died on the eve of the Grammy Awards in Los Angeles at the same hotel where her mentor, record mogul Clive Davis, was holding an annual pre-event party featuring scores of music industry celebrities.

A dramatic scene unfolded at the Beverly Hilton hotel as guests arriving for the party expressed shock at her death, while reporters swarmed the hotel, fans gathered outside to light candles in her memory and helicopters hovered overhead.

Beverly Hills police said they were called to the Beverly Hilton at around 3:43 p.m. PST, and fire department personnel who were already at the location responded immediately. Houston was in her fourth-floor room but was unresponsive to CPR, and she was pronounced dead at 3:55 p.m.

"She has been positively identified by friends and family (who) were with her at the hotel, and next of kin have already been notified," Lieutenant Mark Rosen told reporters. Police said there were no obvious signs of criminal intent.

Los Angeles County coroners removed Houston's body from the hotel after midnight through a backdoor to avoid the crush of media set up to cover her shocking death.

Typically, coroners conduct an autopsy within a day or two, at which point they might release some preliminary information about the death. If drugs or alcohol are involved, however, an official cause of death would not be released until after toxicology tests, which could take six to eight weeks.

BRILLIANT CAREER

Tributes poured in from around the world for a singer whose remarkable vocal power and range produced some of the most memorable music of her generation, including her signature hit, "I Will Always Love You."

"I don't have to mask my emotion in front of a room full of so many dear friends," Davis told a somber crowd at his gala dinner and party just hours after Houston's death. "I am personally devastated by the loss of someone who has meant so much to me for so many years."

Neil Portnow, president of the Recording Academy, which runs the Grammys, told the audience at Davis's party that Jennifer Hudson would sing a tribute to Houston at Sunday night's Grammy Awards.

"We will do something appropriate tomorrow, and nothing could be more appropriate than having Jennifer Hudson sing on stage for Whitney," Portnow said. "In our community, we celebrate things ... let's celebrate Whitney Houston."

Outside the hotel in the wealthy enclave of Beverly Hills, a phalanx of hotel security personnel guarded the perimeter to prevent reporters and fans from entering. Some of Houston's admirers gathered on the sidewalk, lighting candles and singing her songs.

Over the course of a 30-year career in which she established herself as one of the most-admired and influential singers of her time, Houston won six Grammys, 30 Billboard awards and 22 American Music Awards. She released seven studio albums and sold some 170 million CDs, singles and videos. The soundtrack for a hit movie in which she starred, "The Bodyguard," was among the best-selling soundtracks in movie history.

Her 1985 debut, "Whitney Houston," became the best-selling debut album by a female act at that time, and spawned several hits including "How Will I Know." Her second studio CD, 1987's "Whitney," became the first album by a female artist to debut at No. 1 on the Billboard 200 albums chart.

She crossed over from music success to TV and movies, appearing in "The Bodyguard" (1992), as well as "Waiting to Exhale" (1995) and "The Preacher's Wife" (1996).

Born in Newark, New Jersey, in 1963, Houston was inspired to perform as a child by soul singers in her family, including mother Cissy Houston and cousins Dionne Warwick and the late Dee Dee Warwick. Her godmother was Aretha Franklin.

"I just can't talk about it now," Franklin said in a statement. "It's so stunning and unbelievable. I couldn't believe what I was reading coming across the TV screen. My heart goes out to Cissy, her daughter Bobbi Kris, her family and Bobby (Brown)."

PERSONAL TURMOIL

By the early 1990s, Houston reigned as the queen of pop, but her critical and commercial success on stage was accompanied by an increasingly troubled personal life. In 1992 she married singer Bobby Brown, who had a bad-boy reputation, and their tumultuous 14 years together were marred by drug abuse and domestic violence.

In 2000, she and Brown were stopped at an airport in Hawaii and security guards discovered marijuana in their luggage. In a 2002 TV interview, she admitted using marijuana, cocaine, alcohol and prescription drugs.

The pair also starred in a reality TV series, "Being Bobby Brown," which painted an often unflattering portrait of the couple.

The last 10 years of Houston's life were dominated by drug use, rumors of relapses and trips to rehab.

She launched a comeback tour in 2009, and in April 2010 she called media reports she was using drugs again "ridiculous." In May 2011, Houston enrolled in a drug and alcohol rehab program.

Despite her personal troubles, Houston commanded great affection among her music industry colleagues, and emotional tributes flooded the media in the hours after news broke of her death.

"I am absolutely heartbroken at the news of Whitney's passing," legendary music producer Quincy Jones said in a statement. "... I always regretted not having had the opportunity to work with her. She was a true original and a talent beyond compare. I will miss her terribly."

Barbra Streisand said in a statement: "She had everything, beauty, a magnificent voice. How sad her gifts could not bring her the same happiness they brought us."

Pop star Rihanna posted on Twitter "No words, just tears."