Talks to halt violence that has killed at least 1,000 people in South Sudan faced further delay on Wednesday after the government rejected rebel calls for immediate release of detainees.

The three weeks of fighting, often along ethnic faultlines, pitted President Salva Kiir’s Sudanese Peoples Liberation Army, SPLA, forces against rebels loyal to former Vice President Riek Machar, and brought the oil rich nation close to civil war.

Both sides met face-to-face for the first time on Tuesday in Addis Ababa but quickly took a break for African mediators to head to Juba and push for the release of 11 rebel detainees who were arrested last year over an alleged coup plot.

But Kiir’s government rejected the request, saying the detainees would only be fereed as long as the requisite legal processes have taken place.

“We are willing to hear what the IGAD mediators will suggest and we will confer as a group,” said Mabior Garang, spokesman of Machar’s delegation to the talks in the Ethiopian capital.

“It is a decision that we will have to make as a group,” Garang said when asked whether Machar’s delegation would withdraw from the talks unless the detainees were freed.

IGAD is the East African group leading the talks and Its mediators were set to arrive in Addis Ababa on Wednesday evening.

The rebels had initially demanded the release of the detainees before the talks, but have since agreed to negotiate a ceasefire and the status of the detainees.

The fighting is the worst in South Sudan since it won independence from Sudan in 2011 in a peace deal that ended one of Africa’s longest civil wars.

It has also displaced over 200,000 people and cut oil exports.