South Sudanese forces have arrested the petroleum minister and several senior military officials allied with First Vice President Riek Machar, a vice presidential spokesperson said, potentially jeopardising a peace deal that ended the civil war.

South Sudan has formally been at peace since the 2018 agreement ended a five-year conflict between Machar and President Salva Kiir that killed hundreds of thousands of people. The two men still share a fractious relationship and violence between rival communities flares up frequently.

Machar’s spokesperson Puok Both Baluang said Petroleum Minister Puot Kang Chol and the deputy head of the army were arrested, while all other senior military officials allied with Marchar were placed under house arrest.

“As of now, there’s not any reason provided to us that led to the arrest or the detention of (these) officials,” Baluang told Reuters.

South Sudanese troops were also deployed around Machar’s residence, although the vice president had been able to travel to his office on Wednesday morning, Baluang said.