Nairobi - South Sudan rebel leader Riek Machar says he cannot leave his home in South Africa without first informing South African authorities.Machar told The Associated Press in a phone interview that he can move freely, but "I am to inform them I want to go somewhere and they take me there".He says this is for his protection. When asked if he is under house arrest, he referred the question to South African authorities, saying: "I am their guest, so you ask them."South Africa's foreign affairs ministry has said it was "taking care" of Machar and expressed concern about reports claiming house arrest. South Africa's foreign affairs spokesperson Clayson Monyela was not reachable by phone on Sunday.Machar resumed his vice president role under his rival, President Salva Kiir, this year but fled the country in July after fighting erupted in the capital amid a three-year civil war.He has said he crossed on foot into the Democratic Republic of Congo, then spent time in Sudan. He told the AP in October that he was in South Africa for medical tests and was waiting for the chance to meet South African President Jacob Zuma.South Sudan's president quickly replaced Machar as vice president after he left the country.In his latest interview, Machar rejected a national dialogue process that Kiir announced last week as "bogus." Machar said there must be peace talks to end the civil war before any such dialogue takes place.Tens of thousands have been killed in South Sudan's civil war, and more than a million refugees have fled the country. The United Nations recently warned that the country is at risk of genocide as fighting escalates in the southern Equatoria region.