South Sudan’s President Salva Kiir has announced a night time curfew and said an attempted coup by soldiers loyal to his sacked former deputy Riek Machar has been quashed.
The curfew comes after heavy gunfire and explosions overnight in the capital, Juba.
Dressed in battle fatigues at a news conference, Mr Kiir said the government was in full control of the capital, and announced the nighttime curfew for civilians.
Several people are reported to have been wounded and hundreds of people have sought refuge at the UN mission in Juba.
The UN has expressed concern and appealed for calm.
Tensions have been high in South Sudan – the world’s youngest country – since President Kiir sacked his entire cabinet, including his deputy in July in an apparent power struggle.
Mr Machar now leads a dissident faction within Mr Kiir’s ruling party.
The two men are from rival ethnic groups that have clashed in the past.
The fighting in Juba broke out overnight with reports of continuous gunfire and several explosions.
The city’s airport has been closed and the state TV channel went off air for several hours.
Shortly after it came back on air, the state television channel SSTV broadcast an address from Mr Kiir, wearing military uniform rather than his usual civilian clothing and flanked by government officials.
He said the violence “was an attempted coup”, but that the government was “in full control of the security situation in Juba’‘.