According to BBC News, Pelli's death on Friday was reported by the Governor of Argentina's Tucuman province, Juan Manzur.
Pelli and his New Haven, Conn. -based firm have created more than 100 major projects including office buildings, museums, residential towers and libraries.
The twin 1,483ft skyscrapers are among the world's tallest buildings.
Leading the tributes was Argentina's President Mauricio Macri, who tweeted that Pelli's legacy was "a pride for all Argentines".
He also designed Gaviidae Common in downtown Minneapolis, completed in 1989, and Duluth's Weber Music Hall, which opened in 2002.
His other notable projects included New York's World Financial Centre; the Gran Torre Santiago skyscraper in Chile and most recently the Transbay Transit Center in San Francisco which opened in 2018.
He received numerous awards in his career, including the Aga Khan Award in Architecture in 2004 for designing the Petronas Towers.
He founded Cesar Pelli & Associates Architects with his wife Diana Balmori, a landscape architect, and his former colleague Fred Clarke in 1977.
Pelli also served as dean of Yale University's School of Architecture. That same year, he opened his own firm, César Pelli & Associates, in New Haven, Conn., and received the coveted opportunity to design the expansion of the Museum of Modern Art in NY.
Architects must deliver "what is needed of us", Pelli once wrote.