Museveni was met at the airport by South Sudan's President Salva Kiir, whose administration has accused First Vice President Riek Machar of stoking rebellion and put him under house arrest.

The Ugandan leader, whose military was invited into South Sudan last month to help secure the capital, did not refer directly to the crisis in public remarks at the airport in Juba.

The visit follows mediation missions by the African Union and an East African regional body this week aimed at de-escalating the crisis.

Museveni told reporters he would hold talks "aimed at strengthening bilateral relations and enhancing cooperation between our two nations". Kiir said the two leaders would discuss "current political developments in the country".

The standoff between Kiir and Machar, who led opposing forces in a 2013-2018 civil war that killed hundreds of thousands, has led the United Nations to warn that the world's young nation could be on the brink of all-out conflict along ethnic lines.

Uganda backed Kiir's forces during the civil war and sent troops last month amid fighting between South Sudan's military and an ethnic Nuer militia in Upper Nile state in the northeast.

Machar's mostly Nuer forces were allied with the White Army militia during the civil war, but his party denies government accusations of ongoing links.

Uganda's military chief Muhoozi Kainerugaba, who is also Museveni's son, said on Tuesday he had ordered Ugandan forces to stop attacking the White Army so long as it ceases offensives against Ugandan troops.

Machar's party says the Ugandan intervention is a violation of South Sudan's arms embargo.

Analysts say Kiir, 73, appears to be attempting to shore up his position amid discontent within his own political camp and speculation about his succession plan.

--Reuters--