South Sudanese rebel leader George Athor has been killed in a clash with the army of the newly independent nation, Riek Machar, the vice-president, said.

Athor, who launched a revolt against the government of South Sudan last year, died on Monday after a South Sudanese border patrol clashed with "elements" with him in Morobo County at about 1500 GMT, Machar said in a statement.

"George Athor and one other soldier were killed instantly," Machar said, adding that Athor had been on a recruiting drive outside South Sudan but had sneaked back in.

The News Agency of South Sudan reported that Athor was travelling from Rwanda ad was trying to infiltrate South Sudan after driving through Uganda and eastern Democratic Republic of Congo.

He was planning to recruit fighters in Central Equatoria state, said the news agency,

"His body is going to be handed over to his relatives for burial," Machar said, calling on Athor's followers to heed an amnesty and pardon declared in July when the south formally became independent from Khartoum after decades of civil war.

"I call on all who rebelled against the government to lay down their arms and join the process of peace and development," Machar said.

Athor's death came nearly a month after his first public appearance since launching his rebellion in April 2010 after losing the race for governor in Jonglei state.

"People must die so we can have peace and can have democracy," the former general in the South Sudanese army said after an earlier meeting with South Sudanese President Salva Kiir in Nairobi, the Kenyan capital.

"There is a grave need for peace in South Sudan but unfortunately the other side were not co-operating," the militia leader said. He sought fresh nationwide elections and "two or three ministerial posts".

"President Kiir was positive but that was not the same for the rest of the delegation," he said.

Source: Agencies