South Sudan crisis: East Africa would not accept coup
The leaders of Ethiopia, South Sudan and Kenya met in Juba on Thursday East Africa's leaders have said they would not accept a violent overthrow of the government in South Sudan, where more than 1,000 people are believed to have died in recent clashes.
Kenya's president also called for an immediate end to the fighting and for talks with both sides.
The UN is sending extra peacekeepers to the world's newest country.
The clashes come amid a power struggle between President Salva Kiir and his former deputy, Riek Machar.
There are reports of mass killings along ethnic lines, targeting both members of Mr Kiir's Dinka ethnic group and Mr Machar's Nuer community.
The fighting has forced more than 100,000 to flee their homes, with about 60,000 seeking refuge at UN compounds across the country, UN officials say.
'Give peace chance'Anne Soy reports: ''Many here are too frightened to venture out of the UN camp in Juba''
East African regional leaders from the eight-member bloc, known as Igad, are meeting in Kenya's capital Nairobi after the leaders of Kenya and Ethiopia met President Kiir in South Sudan's capital Juba on Thursday.
However, BBC South Sudan analyst James Copnall says there is no sign of the key step in solving this crisis - direct talks between the two protagonists.
President Kiir is the only Igad leader not attending the Nairobi talks but a Kenyan official sought to downplay his absence.
"Kiir is not coming because [Ethiopian Prime Minister Hailemariam] Desalegn and [Kenyan President Uhuru] Kenyatta met him yesterday in Juba. Everything they needed to discuss was discussed," a State House official told the Reuters news agency.
He is being represented by senior officials.
China, which buys most of South Sudan's oil, has also sent an envoy to the region to try to negotiate an end to the fighting.
"Let it be known that we in Igad will not accept the unconstitutional overthrow of a duly and democratically elected government in South Sudan," President Kenyatta said at the start of the talks.
"Violence has never provided optimum solutions - violence begets more violence," he said.
Rebecca Garang, widow of John Garang, who led south Sudanese rebel forces against Khartoum for many years, told the BBC's Newsday programme she was "optimistic" about the Nairobi talks and welcomed the regional intervention.
She said her late husband would not have been happy with the fighting in the world's newest country.
"Those people who have died for the cause of this country would not be happy with what we are doing today," she said.
The head of the UN mission in South Sudan, Hilde Johnson, on Thursday called on the country's political leaders "to give peace a chance".
"The nation that [was] painstakingly built over decades of conflict and strife is at stake," she said, speaking via a video link from Juba.
A number of towns have been devastated during the almost two days of fighting 
The UN says more than 100,000 civilians have fled their homes The UN Security Council has voted to almost double the number of peacekeepers to 12,500.
'Oil wells seized'Ms Johnson said there had been heavy fighting in Malakal and Bor, while the town of Bentiu had become calmer.
Ethiopia's Foreign Minister Tedros Adhanom: ''Any solution to this crisis should be through political dialogue''
The fighting is also affecting oil production, which accounts for 98% of government revenue.
Ms Johnson said there had been internal tension within the governing Sudan People's Liberation Movement (SPLM) before the outbreak of violence.
But, she said, no-one had expected "the unravelling of [South Sudan's] stability so quickly".
The violence first erupted after a meeting of the SPLM's high council, when President Kiir accused the former vice-president, who had been sacked in July, of plotting a coup.
Mr Machar denied any involvement and said the accusations were an attempt by Mr Kiir to get rid of his political rivals.
The fighting quickly spread to half of Sudan's 10 states.
South Sudan has been beset by a series of rebellions since becoming independent from Sudan in 2011.
Fighting erupted in the South Sudan capital, Juba, in mid-December. It followed a power struggle between President Salva Kiir, a Dinka, and his Nuer ex-deputy Riek Machar. The fear is that the rivalry will spark a widespread ethnic conflict. According to OCHA, 81,000 people have been forced from their homes. 
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. 
Both Sudan and the South are reliant on oil revenue, which accounts for 98% of South Sudan's budget. They have fiercely disagreed over how to divide the oil wealth of the former united state - at one time production was shutdown for more than a year. Some 75% of the oil lies in the South but all the pipelines run north 
The two Sudans are very different geographically. 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. 
After gaining independence in 2011, South Sudan is the world's newest country - and one of its poorest. Figures from 2010 show some 69% of households now have access to clean water - up from 48% in 2006. However, just 2% of households have water on the premises. 
Just 29% of children attend primary school in South Sudan - however this is also an improvement on the 16% recorded in 2006. About 32% of primary-age boys attend, while just 25% of girls do. Overall, 64% of children who begin primary school reach the last grade. 
Almost 28% of children under the age of five in South Sudan are moderately or severely underweight - this compares with the 33% recorded in 2006. Unity state has the highest proportion of children suffering malnourishment (46%), while Central Equatoria has the lowest (17%). 
Have you been affected by the issues in this story? You can send us your comments and experience using the form below.