The 13 United Nations mission staff that were taken hostage by a group of 100 unarmed South Sudanese refugees in the Democratic Republic of the Congo have been released.

The hostage takers were among 530 people living in the Munigi base outside Goma since fleeing South Sudan last August, the UN’s Goma bureau head, Daniel Ruiz, told Reuters. Most are former fighters loyal to the former vice-president Riek Machar.

“The camp is quiet and under full control of Monusco [(the peacekeeping mission],” UN peacekeeping spokeswoman Ismini Palla said. “All staff have returned safely to their homes. No casualties have been reported. The mission is investigating the incident.”

Machar’s supporters have been involved in clashes with President Salva Kiir’s forces since last July. The UN estimates about 3 million South Sudanese have been uprooted by the violence, the biggest cross-border exodus in Africa since the 1994 Rwandan genocide.

Ruiz said the camp occupants had been demanding to be moved for months. The government of the DRC, mindful of threats to its stability from past refugee influxes and from armed groups in its volatile east, is also keen to move them.

On Friday, eight of them agreed to be repatriated to South Sudan’s capital, Juba. Others fear going back and are frustrated at being confined in the tiny camp.

“They’re saying if the eight were transferred to South Sudan, why shouldn’t we be able to go to a third country?” Ruiz said. He added that the UN mission was currently negotiating with them.

Civil war broke out in oil-producing South Sudan in 2013 after Kiir sacked Machar from the vice-presidency. The conflict ended with a peace pact in 2015 and Machar was reinstated early last year but tensions between the two men lingered and new fighting began in July.