Uganda has deployed an unknown number of troops to South Sudan in a bid to protect the fragile government of President Salva Kiir as a tense rivalry with his deputy threatens a return to civil war in the east African nation.

Uganda has deployed special forces in South Sudan's capital Juba to "secure it", Uganda's military chief said on Tuesday, but South Sudan's information minister denied the presence of troops, as tensions between South Sudan's president and first vice president stoke fears of a return to war.

Uganda has deployed special forces to South Sudan's capital, Juba, to help President Salva Kiir to "secure it", Uganda's military chief Gen Muhoozi Kainerugaba has said. The move comes as tensions escalate between Kiir and his deputy Riek Machar,

The situation in South Sudan is fragile and getting worse, with growing political and military instability. The claims made by the information minister do not reflect the reality on the ground.

Uganda's military chief said Tuesday his country had deployed special forces in South Sudan's capital Juba to "secure it" as tensions between President Salva Kiir and his First Vice President Riek Machar stoke fears of a return to civil war.