South Sudan forms unity govt

South Sudan's transitional unity government was sworn into office yesterday, with President Salva Kiir sharing power with ex-rebels in a key step in a long-delayed peace process.

Under terms of an August 2015 peace deal, the 30 ministerial posts are split between Kiir, former rebel chief turned first vice president Riek Machar, opposition and other parties.

"We are going to work together," Kiir said after the ministers were sworn into office, and he shook hands with Machar. "We must learn how to forgive and we must learn how to apologise."

UN Secretary-General Ban Ki-moon said the naming of the ministers was an "important milestone" in the peace process, urging the parties "to cease immediately all hostilities". The transitional government is to remain in place until October 2018.

Machar returned to the capital Juba on Tuesday and was immediately sworn into the post of vice president -- a position he was sacked from five months before war broke out. Fighting erupted in December 2013 when Kiir accused Machar of plotting a coup, claims he always denied.

The conflict, which has torn open ethnic divisions, has been characterised by horrific rights abuses, including gang rapes, the wholesale burning of villages and cannibalism.

Ensuring they work together in a unity government, and that the thousands of rival armed forces now in separate camps inside the capital keep their guns quiet, will be a major challenge.

Tens of thousands of people have been killed and more than two million driven from their homes in the conflict, which has reignited ethnic divisions and been characterised by gross human rights abuses.