South Sudan's government insisted on Tuesday it was "not at war" after days of heavy fighting against rebel forces that has displaced more than 180,000 people.
Fighting erupted in Jonglei state, north of the capital Juba, in late December, in the latest clashes between factions loyal to President Salva Kiir and his long-time rival, Riek Machar.
"The ongoing security operation in northern Jonglei State is a lawful and necessary measure aimed at halting the advance of rebel forces, restoring public order and safeguarding civilians," Information Minister Ateny Wek Ateny told reporters in Juba.
"The country is not at war. We are only stopping the advancement" of the opposition forces, he said.
South Sudan is the world's youngest country and has been beset by civil war, poverty and massive corruption since it was formed in 2011.
Supporters of Kiir and Machar fought a civil war from 2013 and 2018, and the subsequent peace deal has been unravelling over the past year.
But Ateny insisted "the peace agreement has not collapsed".
Machar has nevertheless been kicked out of the power-sharing government and is on trial for "crimes against humanity".
Since late December, his forces have seized parts of Jonglei, triggering a violent response from the government, including the "indiscriminate" use of barrel bombs on civilian areas, according to witnesses and NGOs speaking to AFP by phone.
A senior general, Johnson Olony, was filmed ordering troops to "spare no lives" in Jonglei.
Government spokesman Ateny said this "might have been a slip of the tongue".
On Tuesday, the African Union condemned "calls for... violence against civilians" and urged "all parties to exercise maximum restraint, immediately de-escalate tensions and fully comply with their obligations under the R-ARCSS".
R-ARCSS is the acronym for peace agreement known as the Revitalised Agreement on the Resolution of the Conflict in the Republic of South Sudan.
South Sudanese authorities estimate the number of displaced in Jonglei at more than 180,000, the United Nations humanitarian agency OCHA said last week.
Amid reports of blocks on humanitarian access, NGOs like Doctors Without Borders (MSF) say they have struggled to supply teams in Jonglei, leading to "catastrophic" shortages.
"What we are witnessing in Jonglei is not an isolated security incident," Barney Afako, a member of the UN Commission on Human Rights in South Sudan, said last week.
"It is a dangerous escalation which is manifesting in other parts of the country as well."
