"Irena, Warsaw will always be grateful to you," Mayor Rafał Trzaskowski wrote in a social media post. "We will always remember you."
Paśnik, née Szyperska, was born on October 4, 1925. She was 18 when the uprising against Nazi German occupation began on August 1, 1944.
She served as a liaison officer and medic with the Baszta unit and also used the alias "Miła."
Calling her "a heroine of Warsaw," Trzaskowski wrote that she had "passed away to eternal guard."
He noted that she would have celebrated her 101st birthday in October.
The Warsaw Uprising lasted 63 days before being crushed by better-equipped and more numerous German forces.
The fighting left the Polish capital in ruins and claimed the lives of about 18,000 resistance fighters and an estimated 200,000 civilians.
The uprising is seen as one of the most heroic and tragic chapters of Poland's World War II history and the largest military operation carried out by an underground resistance movement in German-occupied Europe.
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Source: PAP