Karlheinz Stockhausen, whose electronic works made him one of Germany's most important postwar composers, has died, German state broadcaster ZDF reported Friday. He was 79.

Stockhausen, who gained fame with avant-garde compositions in the 1960s and '70s and later moved to huge music theater and other projects, died Wednesday, ZDF said, citing the Stockhausen Music Foundation. It gave no cause of death.

Stockhausen's electronic compositions are a radical departure from musical tradition and incorporate influences as varied as psychology, the visual arts and the acoustics of a particular concert hall.

He provoked controversy in 2001 after describing the Sept. 11 attacks as "the greatest work of art one can imagine" during a news conference in the northern German city of Hamburger, where several of the hijackers had lived.

The composer later apologized for his remarks, but the city still canceled performances of his works.