NEW YORK (AP) — Shirley Verrett, an acclaimed American mezzo-soprano and soprano praised for her blazing intensity during a career that spanned four decades, died on Friday in Ann Arbor, Michigan. She was 79.

Verrett, one of the top opera singers of the 1970s and 1980s, had been suffering from heart trouble, said Jack Mastroianni of IMG Artists, who was notified of her death by the Metropolitan Opera Guild.

Born in New Orleans, she was renowned for a blazing intensity in her performances as a mezzo for much of her career and a soprano in her later years. She battled racial prejudice in a predominantly white European-centred art form during a 40-year biracial marriage, according to her autobiography.

Verrett studied at the Juilliard School in New York and was a 1961 winner of the Metropolitan Opera National Council Auditions.

Known early in her career as Shirley Verrett-Carter, she made her professional debut in 1957 and a year later appeared for the first time at the New York City Opera as Irina in Weill's "Lost in the Stars." She also appeared in the first televised Young People's Concert by conductor Leonard Bernstein and the New York Philharmonic from the Lincoln Center for the Performing Arts.

A debut followed at London's Royal Opera in 1966 as Ulrica in Verdi's "Un Ballo in Maschera," and two years later she made her Metropolitan Opera debut in the title role of Bizet's "Carmen," a role she has sung to acclaim at the Spoleto Festival in 1962.

"She is good-looking, and she has a beautiful voice that moves smoothly from low tones to high and plays around freely in the treacherous middle without audible shifting of vocal gears," Allen Hughes wrote in The New York Times. "She also has an attractive stage manner and personality. She laughs easily and convincingly, flirts beguilingly and registers changes of attitude and feeling without hamming or posing."

A year later, she appeared at Milan's Teatro alla Scala in Saint-Saens' "Samson et Delilah." In 1988, she opened the San Francisco Opera season with Placido Domingo in Meyerbeer's "L'Africaine."

Verrett was part of the second generation of black opera singers who followed Anderson's breakthrough at the Met in 1955. Coming after Leontyne Price, she was in a small group of black headliners that included George Shirley, Grace Bumbry, Reri Grist and Martina Arroyo.

Verrett's Met career lasted until 1990, and she sang soprano roles that included Puccini's "Tosca" (opposite Luciano Pavarotti), Bellini's "Norma," Leonore in Beethoven's "Fidelio" and the title role in Verdi's "Aida" and Desdemona in Verdi's "Otello."

In 1973, she sang both Dido and Cassandra in the Met premiere of Berlioz's "Les Troyens" opposite Jon Vickers, replacing an indisposed Christa Ludwig in the latter part. Harold C. Schonberg wrote in the Times that her duets were sung "as beautifully as anybody could desire."

Two years later, she joined Beverly Sills and Justino Diaz at the Met for the US premiere of Rossini's "The Siege of Corinth" under the baton of Thomas Schippers — Sills' long-delayed Met debut. And in 1977, she sang Madame Lidoine in the Met premiere of Poulenc's "Dialogues des Carmelites"

Verrett performed Dido at the opening of Paris' Bastille Opera in 1990 and sang Nettie Fowler on Broadway in Rodgers and Hammerstein's "Carousel" in 1994. AP drama critic Michael Kuchwara wrote she seemed "a little at sea, swallowing some of Hammerstein's best lyrics."

In 1999, she appeared off-Broadway in the musical-comedy "In Dahomey." Three years later, she sued the recording company BMG Classics, alleging her performance was used in the Oscar-winning foreign movie "Life is Beautiful" but she was never paid. The case was dismissed.

Her autobiography, "I Never Walked Alone," was published in 2003.

She joined the University of Michigan School of Music, Theatre & Dance in 1996 and was its James Earl Jones Distinguished University Professor of Music when she retired last May.