An outbreak of cholera in South Sudan is “rapidly escalating”, a humanitarian group has warned, more than a month after the first suspected case was detected.

Doctors Without Borders, known by its French acronym MSF, said on Friday that a total of 737 cholera cases were reported in Malakal, the capital of South Sudan’s Upper Nile state.

“The situation in Malakal remains critical, and we are concerned that the outbreak is spreading to neighbouring areas such as Tonga and Kodok,” Zakaria Mwatia, MSF’s head of mission in the country, said in a statement.