South Sudan's Salva Kiir excludes Riek Machar from cabinet
South Sudan's President Salva Kiir has appointed a new smaller cabinet after sacking his entire previous team last week, a state decree says.
However, he is yet to fill the key post of vice-president after ousting Riek Machar from the post.
The dismissal of the cabinet followed an apparent power struggle between Mr Kiir and Mr Machar.
Oil-rich South Sudan became independent in 2011, making it the world's youngest country.
Numerous armed groups remain active in the country.'Feared commander'
The US expressed concern that the cabinet's dismissal could threaten South Sudan's stability.
Mr Kiir's office said he had acted to promote efficiency and good governance.
The BBC's Nyambura Wambugu reports from the capital, Juba, that Mr Kiir may want to gauge public reaction to his appointments before choosing a new vice-president.
Mr Kiir appointed the governor of the violence-hit Jonglei state, Kuol Manyang, to the key post of defence minister.
He was a feared guerrilla commander during the decades-long rebellion against Khartoum's rule.
More than 100,000 people have fled their homes in Jonglei in recent months, fleeing bitter rounds of ethnic violence and battles between the army and rebels.
Many people she spoke to see the new cabinet as a reflection of loyalty to the president, our reporter says.
Those seen to be critical of Mr Kiir have not been reappointed, including Pagan Amum, former head of the governing Sudan Peoples' Liberation Movement (SPLM), she adds.
Some see this as a blessing for South Sudan because it might push the ejected ministers and their deputies to form a formidable political block that can stand up to the SPLM, our reporter adds.
After his dismissal, Mr Machar said he planned to challenge Mr Kiir for the leadership of the SPLM so that he can run for president in the 2015 election.
Mr Kiir slashed a third of the posts in the cabinet, appointing 10 ministers, AFP news agency reports.
He retained Stephen Dhieu Dau as oil minister, but rung the changes in most other portfolios, it adds.
Both Sudan and the South are reliant on their oil revenues, which account for 98% of South Sudan's budget. But the two countries cannot agree how to divide the oil wealth of the former united state. Some 75% of the oil lies in the South but all the pipelines run north. It is feared that disputes over oil could lead the two neighbours to return to war.
Although they were united for many years, the two Sudans were always very different. The great divide is visible even from space, as this Nasa satellite image shows. The northern states are a blanket of desert, broken only by the fertile Nile corridor. South Sudan is covered by green swathes of grassland, swamps and tropical forest.
Sudan's arid north is mainly home to Arabic-speaking Muslims. But in South Sudan there is no dominant culture. The Dinkas and the Nuers are the largest of more than 200 ethnic groups, each with its own languages and traditional beliefs, alongside Christianity and Islam.
The health inequalities in Sudan are illustrated by infant mortality rates. In South Sudan, one in 10 children die before their first birthday. Whereas in the more developed northern states, such as Gezira and White Nile, half of those children would be expected to survive.
The gulf in water resources between north and south is stark. In Khartoum, River Nile, and Gezira states, two-thirds of people have access to piped drinking water and pit latrines. In the south, boreholes and unprotected wells are the main drinking sources. More than 80% of southerners have no toilet facilities whatsoever.
Throughout the two Sudans, access to primary school education is strongly linked to household earnings. In the poorest parts of the south, less than 1% of children finish primary school. Whereas in the wealthier north, up to 50% of children complete primary level education.
Conflict and poverty are the main causes of food insecurity in both countries. In Sudan, many of the residents of war-affected Darfur and the border states of Blue Nile and South Kordofan, depend on food aid. The UN said about 2.8m people in South Sudan would require food aid in 2013. The northern states tend to be wealthier, more urbanised and less reliant on agriculture.