KAMPALA (Reuters) - South Sudanese opposition groups tried to forge a united front on Monday ahead of an expected resumption of peace talks, in the first such meeting since the start of their country’s civil war nearly four years ago, attendees told Reuters.

South Sudan’s civil war, triggered by a feud between President Salva Kiir and his former deputy, has plunged parts of the world’s youngest nation into famine and forced a third of the population - some four million people - to flee their homes.

Representatives of South Sudan’s many armed and unarmed opposition groups met in the Kenyan town of Nyahururu, said Kosti Manibe, a former government minister who was briefly jailed and represents a group of ex-political prisoners.

“I call it like-minded groups who are opposed to the policy that the regime of Salva in (South Sudan’s capital) Juba is pursuing,” Manibe said.

The gathering, expected to last three days, comes after diplomats from the regional bloc IGAD held talks with Kiir in Juba at the weekend to press the government to participate in the planned peace talks in December.

“The opposition is speaking in a cacophony of voices. There is a need to harmonize these voices,” said Majak D’Agoot, another member of the former prisoner group.

Manibe said Kenya’s government had “graciously allowed” the opposition groups to meet in their country, without elaborating.

Kenyan foreign affairs ministry spokesman Edwin Limo said he was not aware of the meeting.

The United Nations says South Sudan’s civil war has resulted in ethnic cleansing and other war crimes.

A Western-backed peace deal between Kiir and his former deputy Riek Machar collapsed last year, spawning the creation of new armed and political groups opposing the government.

Machar’s SPLA-IO rebel group, the country’s largest which still controls swathes of territory in the south and northeast of South Sudan, declined to attend the Nyahururu meeting, according to Nathaniel Oyet, a senior member of the group, saying it may distract from the December talks.

Oyet also cited security concerns in Kenya where SPLA-IO officials have disappeared in the last year, including Machar’s spokesman who was arrested and deported to Juba in 2016.

Among those attending Monday’s meeting in Kenya were representatives of former army general Thomas Cirillo, who is waging an insurgency in the southern region of South Sudan, and other former government officials Lam Akol, Gabriel Changson, and Joseph Bakosoro, all of whom live in exile.

South Sudanese government officials were unavailable for comment on the Kenya meeting.