Miriam Makeba, a South African singer whose voice stirred hopes of freedom among millions in her own country though her music was formally banned by the apartheid authorities she struggled against, died early Monday after performing at a concert in Italy. She was 76.

Miriam Makeba performed in a concert on Sunday night in southern Italy shortly before she died early Monday.

The Associated Press quoted hospital authorities as saying she died following a heart attack after being brought to a hospital in Castel Volturno near Naples in southern Italy. She had been singing at a concert in support of Roberto Saviano, an author who has received death threats after writing about organized crime. Ms. Makeba collapsed as she was leaving the stage, the South African authorities said. The Italian news agency, ANSA, said she died at the private Pineta Grande clinic.

Although she had been weakened by osteoarthritis, her death stunned many in South Africa, where she stood as an enduring emblem of the travails of black people under the apartheid system of racial segregation that ended with the release from prison of Nelson Mandela in 1990 and the country’s first fully democratic elections in 1994.

“One of the greatest songstresses of our time has ceased to sing,” t Foreign Minister Nkosazana Dlamini-Zuma said in a statement. “Throughout her life, Mama Makeba communicated a positive message to the world about the struggle of the people of South Africa and the certainty of victory over the dark forces of apartheid and colonialism through the art of song.”

Widely known as “Mama Africa”, she had been a prominent exiled opponent of apartheid since the South African authorities revoked her passport in 1960 and refused to allow her to return after she traveled abroad. She was prevented from attending her mother’s funeral after touring in the United States.

For 31 years, Ms. Makeba lived in exile, variously in the United States, France, Guinea and Belgium. South Africa’s state broadcasters banned her music after she spoke out against apartheid at the United Nations in 1976 — the year of the Soweto uprising that accelerated the demands of the black majority for democratic change.

“I never understood why I couldn’t come home,” Ms. Makeba said upon her return at an emotional homecoming in Johannesburg in 1990 as the apartheid system began to crumble, according to The Associated Press. “I never committed any crime.”

Music was a central part of the struggle against apartheid. The South African authorities of the era exercised strict censorship of many forms of expression, while many foreign entertainers discouraged performances in South Africa in an attempt to isolate the white authorities and show their opposition to apartheid.

From exile she acted as a constant reminder of the events in her homeland as the white authorities struggled to contain or pre-empt unrest among the black majority.

Ms. Makeba wrote in 1987: “I kept my culture. I kept the music of my roots. Through my music I became this voice and image of Africa, and the people, without even realizing.”

She was married several times and her husbands included the American black activist Stokely Carmichael, with whom she lived in Guinea, and the jazz trumpeter Hugh Masekela, who also spent many years in exile.

In the United States she became a star, touring with Harry Belafonte in the 1960s and winning a Grammy award with him in 1965. Such was her following and fame that she sang in 1962 at the birthday party of President John F. Kennedy. She also performed with Paul Simon on his Graceland concert in Zimbabwe in 1987.

But she fell afoul of the U.S. music industry because of her marriage to Mr. Carmichael and her decision to live in Guinea.

In one of her last interviews, in May 2008 with the British music critic Robin Denselow, she said she found her concerts in the United States . being cancelled. “It was not a ban from the government. It was a cancellation by people who felt I should not be with Stokely because he was a rebel to them. I didn’t care about that. He was somebody I loved, who loved me, and it was my life,” she said.

Ms. Makeba was born in Johannesburg on March 4, 1932, the daughter of a Swazi mother and a father from the Xhosa people who live mainly in the eastern Cape region of South Africa. She became known to South Africans in the Sophiatown district of Johannesburg in the 1950s.

According to Agence France-Presse, she was often short of money and could not afford to buy a coffin when her only daughter, Bondi, died aged 36 in 1985. She buried her alone, barring a handful of journalists from covering the funeral.

She was particularly renowned for her performances of songs such as what was known as the Click Song — named for a clicking sound in her native tongue — or “Qongoqothwane,” and Pata Pata, meaning Touch Touch in Xhosa. Her style of singing was widely interpreted as a blend of black township rhythms, jazz and folk music.

In her interview in 2008, Ms. Makeba said: “I’m not a political singer. I don’t know what the word means. People think I consciously decided to tell the world what was happening in South Africa. No! I was singing about my life, and in South Africa we always sang about what was happening to us _ especially the things that hurt us.”