Namibia's President Hage Geingob has died while receiving medical treatment at a hospital in the capital, Windhoek.
Vice-President Nangolo Mbumba announced that Mr Geingob had died in the early hours of Sunday morning.
"At his side was his dear wife Madame Monica Geingos and his children," Mr Mbumba said in a statement.
The 82-old leader had been diagnosed with cancer and revealed his diagnosis to the public last month.
His office announced he would be travelling to the US for treatment, but would return to Namibia on 2 February.
Mr Geingob became president in 2015 and was serving his second and final term in office.
He underwent an aortic operation last year, and in 2014 he revealed that he had survived prostate cancer.
Namibia is due to hold presidential and parliamentary elections in November.
The governing Swapo party, which has been in power since independence in 1990, has chosen Mrs Nandi-Ndaitwah as its presidential candidate.
She is currently also Namibia's deputy prime minister, and will become the country's first female president if she wins.