Capt. Khalid al-Sawarmy said in an official Sudan news agency report Wednesday that the Sudanese "army provides no support to any rebels in neighboring countries, be they the south or any others."
The leader of Southern Sudan's ruling party condemned the Khartoum government Wednesday for the second day in a row.
Pagan Amum accused Khartoum of supplying a southern warlord with arms on the last day of the south's Jan. 9-15 independence referendum, a vote that passed overwhelmingly and set Southern Sudan on course to split from the north in July.
Warlord Gabriel Tanginye was in Khartoum Jan. 15 and returned to the south with guns, including trucks mounted with machine guns, Amum said. Tanginye was backed by Khartoum during the 1983-2005 north-south civil war, rejoined the southern army late last year and has now realigned with the north, Amum said.
"Can you imagine these cars and these forces armed with uniforms, moved from Khartoum crossing the country on the official roads? This tells you what is happening," Amum said.
In response, Al-Sawarmy accused Southern Sudan's ruling party of arming rebels elsewhere in the country, and said its accusations sought to distract from this.
On Tuesday Amum blamed Khartoum's ruling National Congress Party for backing a "massacre" of more than 200 people by rebels under George Athor last week in Fangak County, a remote area of volatile Jonglei state. Athor's rebellion began after his unsuccessful bid for the governorship of Jonglei in last April's national elections.
"It is common knowledge that all the militia groups are receiving armaments and financing and support from circles within northern Sudan," said Amum. "This is a strategy to destabilize Southern Sudan. I'm sure this will fail, the people of Southern Sudan are so united as you've seen in the referendum."
Amum said the supplying of weapons "definitely must stop," and he said the south's Sudan People's Liberation Movement has opened talks with the National Congress Party, which he said denied the south's accusations.
In a statement, the south's ruling party called on the Khartoum government and the northern Sudanese army to "immediately disengage from sponsoring and reinforcing insurgency groups in (the) south as this is not in the interest of peace and good neighborly relations between the people of north and south and overall security in the region."
Khartoum has used militia leaders to undermine stability in Southern Sudan and the western region of Darfur for years.
On Tuesday, Amum said the southern government would not share its oil revenues after independence in July. Instead, the south will pay pipeline rental fees to Khartoum in order to transport its reserves to Port Sudan on the Red Sea, in northern Sudan.
Strongly worded accusations and deep-seated mistrust seem to once again be mounting between the leaders of north and south at a time when the two sides have not yet reached agreement on a number of key issues regarding future relations between the two regions, including the sharing of oil revenue and the demarcation of the north-south border.
Amum also said that his party has recommended that the southern parliament adopt "Republic of South Sudan" as the region's official name when it declares independence in July.