Chris Cornell's family say they will work closely with the medical examiner to determine his cause of death.

Rocker Chris Cornell, who gained fame as the lead singer of Soundgarden and later Audioslave, has died at age 52, according to his representative.

In a statement to The Associated Press, Brian Bumbery said Cornell, who had been on tour, died on Wednesday night (US time) in Detroit.

Cornell had performed a concert with Soundgarden in the city that night.

Mr Bumbery called the death "sudden and unexpected" and said Cornell's wife and family were shocked.

The statement said the family would be working closely with the medical examiner to determine the cause, and asked for privacy.

Detroit police spokesman Michael Woody said Cornell died at the MGM Grand Detroit hotel.

He said Cornell's wife had called a family friend and asked him to check on the musician — the friend forced open a hotel room door and found Cornell on the bathroom floor.

The Wayne County Medical Examiner's office will make an official determination about the cause of death.

News of Cornell's death prompted scores of tweets expressing sadness. Aerosmith guitarist Joe Perry tweeted: "Very sad news about Chris Cornell today. A sad loss of a great talent to the world, his friends and family. Rest In Peace."

With his powerful, nearly four-octave vocal range, Cornell became one of the driving forces behind the 'grunge' movement in the 1990s.

He was best known as the lead vocalist, songwriter and rhythm guitarist for Soundgarden, which was founded in Seattle alongside similar groups Nirvana, Pearl Jam and Alice in Chains.

Formed in 1984 by Cornell, guitarist Kim Thayil and bassist Hiro Yamamoto, Soundgarden's third studio album, Badmotorfinger, in 1991 spawned enormously popular singles Jesus Christ Pose, Rusty Cage and Outshined, that received regular play on alternative rock radio stations.

Cornell also collaborated with members of what would become Pearl Jam to form Temple of the Dog, which produced a self-titled album in 1991 in tribute to friend Andrew Wood, the late frontman for Mother Love Bone.

Three years later, Soundgarden broke through on mainstream radio with the album Superunknown, which debuted at No. 1 on the Billboard 200 and was nominated for a Grammy for Best Rock Record in 1995.

It included hit singles Spoonman, Fell on Black Days, My Wave, The Day I Tried to Live and Black Hole Sun, which won a Grammy award for Best Hard Rock Performance.

Soundgarden disbanded in 1997 due to tensions in the band, and Cornell pursued a solo career.

In 2001, he joined Audioslave, a supergroup that included former Rage Against the Machine members Tom Morello, Brad Wilk and Tim Commerford. The band released three albums in six years and also performed at what was billed as Cuba's first outdoor rock concert by an American band, though some Cuban artists have disputed that claim.

Audioslave disbanded in 2007, but Cornell and Soundgarden reunited in 2012 and released the band's sixth studio album, King Animal in 2012.

The group was scheduled to perform a large tour of the US during the northern hemisphere's spring.

Cornell also found mainstream success when he collaborated and sang You Know My Name, the theme song for the 2006 James Bond film, Casino Royale.

He also toured the world performing solo acoustically, playing Soundgarden and Audioslave hits as well as selected covers.

In addition to his music, Cornell also became involved in philanthropy and started the Chris and Vicky Cornell Foundation to support children facing challenges, including homelessness, poverty, abuse and neglect.