Hundreds have been killed in the fighting that began Thursday night. South Sudan's government has said at least 272 were killed, including 33 civilians.
President Salva Kiir and former rebel leader, First Vice President Riek Machar, declared separate cease-fires last night. The cease-fires appear to have held so far.
Military trucks are driving up and down Juba's roads with megaphones ordering soldiers back to barracks.
Japan has urged dozens of its nationals including aid workers in Juba to leave the country and dispatched military aircraft to evacuate them following the fighting.
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Private chartered planes flew foreigners out of Juba's reopened airport today, as regional carriers including Kenya Airways had cancelled flights there.
Neighboring Uganda will send troops to Juba to evacuate its citizens, said Ugandan army spokesman Paddy Ankunda.
The fighting in Juba severely threatened a peace deal signed last year between Kiir and Machar that brought them and their supporters into a transitional coalition government in April.
It is "hugely worrying" that the fighting appeared to be spreading outside South Sudan's capital, the UN human rights office in Geneva said today.
Government officials have repeatedly accused the civilians inside the UN bases of being rebels or rebel supporters.
However, South Sudanese nationals trying to escape the capital were prevented from doing so by authorities, according to a security worker in Juba who insisted on anonymity because he is not authorized to speak to the press.
Aid groups are warning about the lack of clean water for the tens of thousands of people sheltering in various sites around Juba as water tankers have not been able to make deliveries.