Ten senior political figures, including the former finance minister, have been arrested in South Sudan after a coup attempt, the government has said.
The authorities are looking to question five other prominent figures, including former Vice-President Riek Machar.
The country has seen two days of violent clashes, which President Salva Kiir blames on soldiers loyal to Mr Machar, who was dismissed in July.
More than 60 soldiers have been killed in the clashes, doctors have said.
The UN says up to 13,000 people have sought shelter from the violence at its compounds in the capital, Juba.
President Kiir said the clashes began when uniformed personnel opened fire at a meeting of the ruling party, the Sudan People’s Liberation Movement (SPLM), on Sunday night.
The violence continued into Monday, until the government said it was back in full control.
But fresh gunfire erupted on Tuesday near the presidential palace and many other areas of Juba.
A night-time curfew is in place, and the US has ordered all non-emergency embassy staff to leave the country.
Former Finance Minister Kosti Manibe, former Justice Minister John Luk Jok and former Interior Minister Gier Chuang Aluong were among the 10 people who the government said had been arrested.
Many were members of the cabinet which was sacked in its entirety in July.
Information Minister Michael Makuei Lueth told the BBC that government forces were continuing to pursue Mr Machar, whose whereabouts have been unclear since the start of fighting on Sunday.
He said Mr Machar is thought to have escaped with some troops, and also stolen some cattle.
Mr Machar leads a dissident faction within the SPLM, and has said he plans to contest the presidential elections in 2015.
Ajak Bullen, a doctor at a military hospital, said at least 66 soldiers had died in the clashes.
“So far, we have lost seven soldiers who died while they were waiting for medical attention and a further 59 who were killed outside,” he told local media.
“They are there at the mortuary and we are arranging for a mass burial,” he told local radio.
South Sudan is facing its biggest challenge since becoming independent
Another hospital, Juba Teaching Hospital, had earlier reported 26 deaths – and it is unclear whether there is any overlap between the figures.
So far the government has only confirmed that 26 people were killed.
It is also unclear whether those who died were fighting for or against the president.
UN Secretary-General Ban Ki-Moon called on President Kiir to make “an offer of dialogue” to his opponents to end the fighting, a UN spokesman told reporters.
In a statement, Mr Ban called on the government to exercise restraint in the management of the situation.
Juba’s airport remains closed and telephone connections have been severely curtailed.
The UN and the US embassy advised their citizens to stay at home. Both denied rumours they were harbouring any political or military figures.
South Sudan – the world’s youngest country and one of the least developed – has struggled to achieve a stable government since becoming independent from Sudan in 2011.
The independence referendum was intended to end a decade-long conflict, led by the SPLM, against the north.
But the oil-rich country remains ethnically and politically divided, with many armed groups active.
James Copnall South Sudan analyst
- The continued clashes are undercutting President Salva Kiir’s claim on Monday that the government was in “full control” of the situation.
- There are two possible – and not necessarily mutually exclusive – explanations for what is happening.
- The first, the president’s version, is that the army is fighting off an attack by soldiers allied to the former Vice-President, Riek Machar.
- The second is that the president has taken advantage of the military flare-up to crack down on many of those who have criticised him.
- A showdown between Kiir and Machar is not unexpected. South Sudan is now at a critical point.
Profile: Riek Machar
- Central figure in Sudanese and South Sudanese politics for three decades
- Member of South Sudan’s second-largest ethnic group, the Nuer
- Married UK aid worker Emma McCune in 1991 – she died two years later in a car accident in Kenya while pregnant
- Was a Sudan People’s Liberation Movement (SPLM) commander and led a breakaway faction for some years in the 1990s
- After 2005 peace deal appointed vice-president of interim government, retaining the post after independence in 2011 until his dismissal in July 2013