JUBA: A rift appeared in one of South Sudan’s two main rival groups Friday, raising the prospect of further turmoil after months of fighting, as members of one faction threatened to replace their leader.

A group inside the SPLM-IO movement issued a statement saying its head Riek Machar should return to the capital Juba and carry on his work in the government, or be removed from office.

Machar, South Sudan’s Vice President, and his SPLM-IO group, have been caught up with more than two years of on-and-off, ethnically charged fighting with supporters of the country’s President Salva Kiir.

Machar left the capital last week after a new outbreak of clashes, saying he would only return when an international body set up a buffer force to separate his forces from the president’s.

“There is no point to come back to be assassinated,” Machar’s spokesman Goi Jooyul Yol told AFP, speaking from the Ethiopian capital Addis Ababa.

“Dr. Machar is still being hunted around Juba,” he said, adding that “we don’t trust” Kiir’s security pledge.

Kiir called on Machar Thursday to return to salvage a peace deal, and a faction of Machar’s own group, led by Mining Minister Taban Deng Gai, said Friday they agreed.

“The decision by the government to give ... Machar an ultimatum is entirely in line with its powers,” William Ezekiel, spokesman for SPLM-IO faction allied to Gai, said.

“On our side, we want him to show up, otherwise we will replace him,” he added.

Machar’s spokesman, James Gatdet, rebuffed the threats, saying Gai’s faction had no official status in the moment.

“Machar ... has communicated to all his military commanders to cut off any communication with General Taban Deng Gai and his few individuals who support the President Kiir’s conspiracy,” he said.

Speaking after a Cabinet meeting attended by some SPLM-IO ministers, Information Minister Michael Makuei said it was up to the party to sort out its internal differences.

“The Cabinet has advised [Machar] to put his house in order so that they decide as to whether someone will be acting in the place of Riek Machar or declare his position vacant,” he told reporters after the meeting.

The most recent fighting in Juba has forced 26,000 people to flee to neighboring Uganda, the U.N. refugee agency UNHCR’s spokesman Andreas Needham told a news conference in Geneva.