Explosions have taken place at an ammunition dump in a government arms depot in a southern Sudanese town.
Exploding shells rained down on Juba, killing at least 24 people and injuring many more.
The shelling lasted for about an hour, destroying large parts of a residential area close to the barracks.
The Red Cross is helping transport wounded residents to hospital. Juba's deputy governor, Simon Wani Ramba, said the shells reached as far as 1km away.
"There is damage all over the town," he told the BBC's Focus on Africa.
A journalist in the city said that the initial blast occurred at about 0930 GMT on Wednesday.
"There was a huge mushroom cloud in the sky and everyone fell on the floor. Explosions were going off every second for about an hour," Gemma Mortensen told the BBC.
The military has cordoned off a large area including the barracks, a military hospital and a market in the west of the city - making it difficult to establish casualty figures.
One resident, called Paul, told the BBC that many houses had burnt down including his neighbour's house.
"Explosions are still going on now," he said, several hours later.
A peace deal signed earlier this year ended a 21-year civil war between the north and south.
Many southern Sudanese who fled during the conflict are now starting to return home - although many towns in the south have little infrastructure.