South Sudan has signed a peace deal with one of the largest rebel groups challenging its authority.

Government spokesman Barnaba Marial Benjamin announced the agreement Tuesday, saying the group — the South Sudanese Democratic Movement — had agreed to lay down its arms under an amnesty offered by President Salva Kiir.

“That agreement is a comprehensive agreement which covers so many areas with regards to the ceasefire, the political and their representation both at the national and the state level, the reintegration into the army for example, the disarmament program, the reparations in the affected areas where they were having their activities.”

He said some of the group's estimated 1,800 rebels would be absorbed into the army.

A rebel spokesman said several senior rebel members would be granted positions in the government.

The South Sudanese Democratic Movement was founded by a renegade general in 2010, after he lost what he claimed was a rigged election for governor of Jonglei state. The general, George Athor Deng, was killed last year.

Athor had begun peace talks with the South Sudanese government, but those talks broke down and Athor had said his forces were prepared to continue fighting against the government.

Athor and his South Sudanese Democratic Movement had been demanding new elections, the release of political prisoners, and the selection of a third party to help enforce any future peace agreement with the government.