Sinead O’Connor, the outspoken Irish singer-songwriter best known for her strong, evocative voice, as showcased on her biggest hit, a breathy rendition of Prince’s “Nothing Compares 2 U,” as well as for her political provocations onstage and off, has died. She was 56.

Her family announced the death in a statement, according to the BBC and the Irish public broadcaster RTE. “It is with great sadness that we announce the passing of our beloved Sinead,” the statement said. “Her family and friends are devastated and have requested privacy at this very difficult time.” No other details were immediately provided.

Recognizable by her wide eyes and shaved head, Ms. O’Connor released 10 studio albums, beginning with the alternative hit “The Lion and the Cobra” in 1987. She went on to sell millions of albums worldwide, breaking out with the 1990 album “I Do Not Want What I Haven’t Got.”

That album, featuring “Nothing Compares 2 U,” a No. 1 hit and MTV staple, won a Grammy Award for best alternative music performance — although Ms. O’Connor boycotted the ceremony, in 1991, citing what she called the show’s excessive commercialism.

Ms. O’Connor rarely shrank from controversy. In 1990, she threatened to cancel a performance in New Jersey if “The Star-Spangled Banner” was played at the concert hall ahead of her appearance, drawing the ire of no less than Frank Sinatra. That same year, she backed out of an appearance on “Saturday Night Live” in protest of the misogyny she perceived in the comedy of Andrew Dice Clay, who was scheduled to host.

But all of that paled in comparison to the uproar caused when Ms. O’Connor, appearing on “S.N.L.” in 1992, ended an a cappella performance of Bob Marley’s “War” by ripping a photo of Pope John Paul II into pieces as a stance against sexual abuse in the Roman Catholic Church. “Fight the real enemy,” she said.

Ms. O’Connor said in 2012 that she had been misdiagnosed as bipolar the year before and that she was suffering from post-traumatic stress disorder stemming from a history of child abuse. “Recovery from child abuse is a life’s work,” she told People magazine.

In 2007, she revealed on Oprah Winfrey’s television show that she had been diagnosed with bipolar disorder and that she had tried to kill herself on her 33rd birthday. Her son Shane died by suicide in 2022, at 17.As her music career slowed, Ms. O’Connor, who had been open in the past about her struggles with mental health, became an increasingly erratic public figure, often sharing unfiltered opinions and personal details on social media.

Several years ago she converted to Islam and started using the name Shuhada Sadaqat, though she continued to answer to O’Connor as well.

A full obituary will appear soon.