Widespread shooting preventing residents from moving in the city.
A "massive explosion" hit shortly after 9 am followed by further blasts in the Tomping area of Juba, home to embassies, the airport and a UN base, said an aid worker.
"It rings through the whole city every time they fire," said the aid worker, who spoke on condition of anonymity because he was not authorized to speak to press. "I think one of the tanks must be near me, my ears are burning."
Considerable fighting has centered around the UN base in the Jebel area, where some 30,000 civilians have taken refuge. The opposition also has a base near Jebel and their leader also has his home there.
Two government helicopters have been bombing areas near the base while ground forces shell the base, including a camp of tens of thousands of displaced civilians, according to a source within the UN compound, who insisted on anonymity because he is not authorized to speak to the press.
Government officials have repeatedly accused the civilians inside the UN bases of being rebels or rebel supporters.
UN peacekeepers have not fired at the troops shelling the base, said the source in the base, who accused the soldiers with UN blue helmets of abandoning their positions.
"UN peacekeepers, they even run away," he said. "They are not stopping it." UN peacekeepers in South Sudan are mandated to use lethal force to protect civilians under imminent threat in South Sudan.
Video broadcast on Chinese state TV showed smoke rising after the attack and Chinese peacekeepers tending to their wounded.
There were 67 injuries and 8 deaths in the UN base yesterday, according to an internal situation report circulated among humanitarian organizations and seen by AP.
The gun battles in the capital are similar to fighting in December 2013 that sparked a two-year civil war in which tens of thousands died and displaced more than 2 million.
