Zindzi Mandela, South Africa’s Ambassador to Denmark and daughter of anti-apartheid icons Nelson and Winnie Mandela, has died at the age of 59, the South African Department of International Relations and Cooperation said Monday.

“Zindzi will not only be remembered as a daughter of our struggle heroes, Tata Nelson and Mama Winnie Mandela, but as a struggle heroine in her own right. She served South Africa well,” Naledi Pandor, Minister of International Relations, said in a short statement Monday morning.

Zindzi Mandela pictured with father Nelson in 1992.

The department said it was still gathering information on the cause of Mandela’s death and expects to release a detailed statement later.

State broadcaster SABC reported that the diplomat died early Monday morning at a Johannesburg hospital.

A spokesperson for the Nelson Mandela Foundation told CNN it is currently consulting with the Mandela family before it issues its own statement.

The foundation earlier posted that on the same day in 1969, Nelson Mandela’s eldest son, Madiba Thembekile Mandela, died in a car crash.

Nelson Mandela died in 2013 at the age of 95.