UN aid co-ordinator: "There were a lot of gunshots and a lot of dead bodies"
New details are emerging of alleged ethnic killings committed during more than a week of violence in South Sudan.
A reporter in the capital Juba quoted witnesses as saying
more than 200 people, mostly from the Nuer ethnic group, were shot by
security forces.Another man in Juba reported that gunmen from the Dinka tribe were shooting people in Nuer districts who did not speak the Dinka language.
South Sudan's government has denied it is behind any ethnic violence.
The reports emerged as UN Secretary General Ban Ki-moon called on the Security Council to add 5,500 UN troops to the 7,000-strong force in South Sudan.
Rebels supporting sacked former vice-president Riek Machar have seized major towns over the past week.
Tens of thousands of people have fled the fighting.
Mr Chang's purge from power was unusually high-profile
As usual, glimpses inside Pyongyang's political machine only seem to highlight how little we know.
The reams of news coverage churned out by North Korea give an unusual impression of instability at the heart of the North Korean regime.
They describe in lurid detail the charges being brought against Chang Song-thaek - everything from plotting a coup to using pornography to "half-hearted clapping" on Kim Jong-un's rise to power.
Photographs of Mr Chang, stooped and under arrest, were broadcast on state media. And the news was broadcast on the city subway.
But how valid are the claims that Mr Chang was plotting to overthrow his nephew?
If Mr Chang was, indeed, executed - something we have no evidence for beyond the word of the North Korean state - we can be fairly sure it was for something serious. Senior officials in Pyongyang are rarely executed, and certainly not in this very public way.
North Koreans read about Chang Song-thaek's execution at subway stations
But was it a coup? The level of public indoctrination following Mr Chang's arrest certainly could suggest some kind of political upheaval or threat.
Several North Koreans have reported covertly to contacts in the South that party meetings, lectures and self-examination sessions have been stepped up, and there's apparently great emphasis on loyalty.
