Gunfire has erupted inside the main army barracks in South Sudan’s capital, where clashes last year sparked wider conflict.
The body of a government soldier lay in the street outside the compound in Juba, Reuters news agency reports.
Witnesses said people in the area have fled to safety.
The government is yet to comment, but reports say the shooting appeared to have been triggered by a dispute over pay within the army.
“We’re fighting over money,” a soldier shouted from the entrance of the Jebel barracks as gunshots rang out, Reuters reports.
A resident of the city told the BBC that black smoke was still coming up from the direction of the base.
Troops loyal to the government have been deployed in heavy numbers in surrounding streets, and roadblocks have been set up, Reuters reports.
The US embassy in Juba has issued a statement, advising its nationals to stay indoors, the AFP news agency reports.
The shooting erupted in the same barracks where fighting between army units sparked off a wider conflict in Africa’s newest nation in which some 860,000 people have fled their homes.
The BBC’s Africa security correspondent Moses Rono says various army units are based in the main barracks.
A ceasefire was agreed between the rebel and government forces towards the end of January, but both sides have accused each other of violating it.
The talks between the two sides taking place in Ethiopia are currently suspended and are expected to resume on 20 March.