JUBA South Sudan Wednesday denied accusations by Khartoum that it was helping rebels in South Kordofan, Sudan's main oil-producing state, where fighting broke out with government troops in June.
The south won independence from the north last month after a January referendum promised in a 2005 peace deal that ended decades of civil war in the vast African country.
Sudan sent a letter to the U.N. Security Council Tuesday accusing the south of causing instability and disrupting peace in the neighbouring state of South Kordofan.
"This is an absolute lie on behalf of the government in Khartoum. We are not giving any support to the rebels," South Sudan's Information Minister Barnaba Marial Benjamin told Reuters.
The Sudan People's Liberation Movement-North (SPLM-N) fought alongside its southern counterpart against Khartoum during the civil war in which some two million people perished.
Benjamin said the ruling Sudan People's Liberation Movement (SPLM) now has no links with the SPLM-N.
Sudan's foreign ministry Tuesday accused the South of "standing behind all hostile activities in South Kordofan" and "supporting it with weaponry and equipment."
Benjamin rejected the charges. "Khartoum is trying to set up a smokescreen to cover up Security Council concerns that they are bombing civilians in South Kordofan," he said.
Rights groups say Khartoum has broken its own cease-fire announced last week in South Kordofan by continuing to bomb civilians indiscriminately, frequently rolling bombs manually out of Antonov cargo planes.
According to a leaked U.N. report, the Sudanese army has carried out killings, arbitrary arrests, abductions, attacks on churches and aerial bombardment in Southern Kordofan which, if proven, might constitute war crimes and crimes against humanity.
Researchers from New York-based Human Rights Watch and London-based Amnesty International say some of these allegations have now been proven.
The Sudanese government has dismissed the U.N. report as unfounded and malicious and has said it will form its own committee to assess the situation in South Kordofan.
Under the 2005 Comprehensive Peace Agreement, South Kordofan and Blue Nile state, which also fell north of the disputed border after the south seceded, were offered popular consultations to decide their future relations with Khartoum, but these have yet to take place.
"(Khartoum) has failed to bring peace to Darfur, South Kordofan and Blue Nile. They are looking for a scapegoat and blaming the South," Benjamin said.
(Reporting by Hereward Holland; Editing by Alistair Lyon)