MOSCOW (AP) -- Irina Arkhipova, a Soviet-era diva who sang at the Bolshoi theater for decades, has died. She was 85.

The director of the Arkhipova Foundation said the singer died Thursday at Moscow's Botkin hospital. A cause of death wasn't specified.

Arkhipova, a mezzo-soprano and later contralto, sang leading roles for the Bolshoi for decades after joining it in 1956. She reached the peak of her career in the 1960s and 1970s, making guest appearances throughout Europe and the U.S.

Her most celebrated roles included Carmen in Bizet's Carmen and Marfa in Mussorgsky's Khovanshchina.