South Sudan's President Salva Kiir ordered a unilateral ceasefire on Monday evening after three days of heavy fighting in the capital that has left hundreds dead.

"The president has reiterated his commitment to the continued implementation of the [peace] agreement in letter and spirit, and thus issues an order of cessation of hostilities with immediate effect," said Information Minister Michael Makuei on state broadcaster SSBC at 6:00pm local time.