Sundan's president, Omar al-Bashir, vowed on Thursday to teach neighbouring South Sudan a final lesson by force by eliminating the government.
The intensification of rhetoric came after a week of clashes and deepened fears that the two countries were on the brink of a return to the conflict that led to their division following a civil war.
Officials in South Sudan's capital, Juba, said four attacks by Sudan had been repulsed in areas lining the country's disputed border.
Dressed in full military uniform, including rows of medals, Bashir told troops preparing to deploy to the border that he would defend Sudan's territory.
"These people don't understand, and we will give them the final lesson by force," he told a rally in El-Obeid, capital of Sudan's North Kordofan province. "We will not give them an inch of our country, and whoever extends his hand on Sudan, we will cut it."
Earlier, he had said that Sudan's main target from today was to liberate the people of South Sudan from their government, made up mostly of former rebel soldiers from the Sudan People's Liberation Movement (SPLM). "We say that it [SPLM] has turned into a disease, a disease for us and for the South Sudanese citizens," Bashir said.
"The main goal should be liberation from these insects and to eliminate them once and for all. Either we end up in Juba and take everything, or you end up in Khartoum and take everything."
Sudan and South Sudan have come close to a return to war in recent months, and pulled back from full conflict to allow for fresh negotiations on contentious issues including demarcating their shared border and sharing oil wealth. But the current escalation is more serious. It began when South Sudan's forces seized the town of Heglig, internationally recognised as being in Sudan, and the oilfields that surrounded it.
Barnaba Marial Benjamin, South Sudan's information minister, claimed that Heglig had always belonged to the south and occupying the town was not an act of war.
"Up to now we have not crossed even an inch into Sudan," Benjamin said yesterday. "The Republic of South Sudan considers the Republic of Sudan to be a neighbour and a friendly nation."
Neither country is financially robust enough to sustain a war since South Sudan shut down its oil industry four months ago after a dispute with Sudan over its charges to transport crude to export terminals on the Red Sea.
This has left both countries struggling for cash. Bashir's position is weakened further by insurrections in Darfur, South Kordofan and Blue Nile.
"Domestic rebellions and probable international condemnation suggest that all-out war could cause political instability in Khartoum," said Robert Borthwick, senior Africa analyst at Maplecroft, a British global risks consultancy.
