Sudan, stepping up its rhetoric, accused South Sudan of "hostility" in their row over oil transit fees and said it would hold Juba responsible for any attack on northern oil facilities, a state-linked news website said on Wednesday.
The two neighbours are locked in a worsening row over disentangling their oil industries after the South split from Sudan and became independent in July, following decades of civil war that ended with a peace deal in 2005.
The landlocked new nation took three-quarters of the oil production - the lifeline of both economies - but needs to pay for using northern export facilities and the Red Sea port of Port Sudan.
Tension rose when Sudan said last month it started seizing southern oil at Port Sudan as compensation for what it called unpaid pipeline transit fees. Juba, the southern capital, responded last week by shutting down its entire output of 350,000 barrels a day.
The African Union has been trying to broker a deal but a meeting between Sudanese President Omar Hassan al-Bashir and his southern counterpart Salva Kiir failed last week. More talks are scheduled for next week.
The Sudanese negotiation team said South Sudan had not been ready to reach a fair deal at the latest round of talks in Addis Ababa, the state-linked Sudanese Media Centre (SMC) said, citing a statement issued by the delegation after its return.
"The Government of Sudan ... called on the southern government to review its hostile leaning towards Sudan," the SMC said, adding that Sudan remained ready to continue talks in "good faith."
Sudan also again accused Juba of supporting rebels in the main northern border state of South Kordofan, the SMC said.
"The Government of Sudan will hold the government of South Sudan responsible for any attempt to target or sabotage oil fields, facilities and oil infrastructure," SMC said, without elaborating.
There was no immediate reaction from Juba. South Kordofan is home to much of Sudan's remaining oil industry after the split.
Fighting broke out in June between the Sudanese army and rebels of the SPLM-North, and clashes spread to Blue Nile in September. Both states border South Sudan.
Blue Nile and South Kordofan contain large groups who sided with the south in the civil war, and who say they have continued to face persecution inside Sudan since South Sudan seceded.
The SPLM is now the ruling party in the independent south and denies supporting SPLM-North rebels across the border.
Events in South Kordofan and Blue Nile are difficult to verify because aid groups and foreign journalists are banned from areas where fighting takes place.
SPLM-North is one of a number of rebel movements in underdeveloped border areas who say they are fighting to overthrow Bashir and end what they see as the dominance of the Khartoum political elite.
The fighting has already forced about 417,000 people to flee their homes, more than 80,000 of them to newly independent South Sudan, according to the United Nations.