Omar al-Bashir, Sudan's president, has said his "main goal" is to free South Sudan's citizens from the ruling Sudan People's Liberation Movement (SPLM) party, after a series of border clashes between the neighbouring countries.
Bashir threatened on Wednesday to overthrow the "insect" government of its southern neighbour following an attack on Sudan's most important oil field, Heglig, by South Sudanese troops who seized it eight days ago.
"Our main goal is liberation of the southern citizens from the SPLM," he told members of Sudan's ruling National Congress Party.
"We call it an insect ... trying to destroy Sudan, and our main target from today is to eliminate this insect completely.
"There are two choices: Either we end up in Juba or they end up in Khartoum. The old borders cannot take us both," Bashir said, predicting that the victory will be swift.
"In a few hours you are going to listen to good news from your brothers in Heglig.
"Heglig will not be the end. The end will be in Juba," the South's capital.
Bashir made the remarks as his audience sang songs about jihad, or holy war.
Swift victory forecast
While Bashir forecast a swift victory, a foreign ministry official said Sudan was pursuing both military and diplomatic measures to get South Sudan out of the area.
"Military steps are under way ... and they are calculated measures," Omar Dahab, head of the ministry's crisis team, said.
|In-depth coverage of North-South strife over border
"At the same time, they are taking into consideration the diplomatic and good offices efforts regarding the ending of the occupation.
"We have to end the occupation by hook or crook, by either way."
Sudan's military has released virtually no information about the situation on the ground but South Sudan has vowed to hold its positions in Heglig, despite air strikes.
Clashes broke out last month in the Heglig area and escalated last week with waves of aerial bombardment hitting the South and South Sudan''s seizure of the oil centre on April 10.
The UN, the US and the EU have criticised the South's occupation of the north's most important oil field, equally denouncing Sudanese air raids against the South.
There are widespread fears that the fighting, which began with skirmishes in the same area in late March and intensified last week, will spread.
It is already the worst since South Sudan won independence in July after a 1983-2005 civil war which killed two million people.
Bashir's comments come following the UN Security Council discussed possible sanctions on Tuesday against Sudan and South Sudan in a bid to halt a wider war.
"Council members expressed grave concern over the situation and committed to make every effort to convince the parties to cease hostilities and return to the negotiating table, " Susan Rice, the Security Council president, said.
But Dahab, of Khartoum's foreign ministry, said penalising both the aggressor and the victim would be wrong.
"It is clear that that is not fair," he said. "Logically it should be directed to the aggressor."
Although South Sudan disputes it, Heglig has been internationally recognised as being part of Sudan.