The army may have retaken the South Sudanese flashpoint town of Bor, but fighting continues elsewhere in the country.
Bor has been heavily fought over since clashes broke out in South Sudan in December.
Uganda deployed troops to the country shortly afterwards. Its army has claimed credit for the operation, while a spokesman for the rebel forces said its troops had made a tactical withdrawal.
At first, Uganda said its armed forces were in South Sudan to assist stranded Ugandans. It has since declared its role in combat.
The UN estimates thousands of people have died and more than half a million driven from their homes as a result of fighting in the world’s newest nation.
Conflict erupted when President Salva Kiir accused his former deputy, Riek Machar, of plotting a coup – something he denies.
Talks aimed at securing a ceasefire have been ongoing in the Ethiopian capital Addis Ababa for several days.