South Sudan rebel leader Riek Machar has said that the government threats to try him for treason were an attempt to derail peace talks, and called for President Salwa Kiir to resign, in his first face-to-face interview since violence erupted in December.

The government said this week that former vice president Machar and six of his allies should face the treason charge, accusing him of trying to launch a coup after fighting broke out between rival groups of soldiers in the capital, Juba.

But Machar rejected the accusation and took refuge in Jonglei state as clashes between forces loyal to him and government troops spread across the oil-producing nation, killing thousands.

"I am not aware of why we should face those charges for an alleged coup that never happened," Machar told Reuters on Friday in his bush hideout. "(It) is another attempt to stop peace talks."

Both sides agreed to negotiations in neighbouring Ethiopia following diplomatic pressure from regional powers, the United Nations and major donors, including Washington. They agreed to a ceasefire last week, but violence has continued.

"It would be best for Kiir to resign. We are due for elections in 2015. Before the elections there would be an interim government," Machar said.

Source: Reuters