Sudan's army says the UN resolution on the conflict in Darfur is "a declaration of war" and threatens to fight any foreign intervention.
Marauding militias are accused of rape and mass murder in Sudan
The resolution gives the government 30 days to disarm the Janjaweed militias, which are accused of widespread atrocities against non-Arab groups.
Sudan's cabinet has also criticised the resolution. It has promised to disarm the Arab militias - but within 90 days.
More than one million people have fled their homes in 18 months of conflict.
The United Nations World Food Programme has stepped up its relief effort in Darfur with its first airdrops of food intended to help families cut off from deliveries by road because of heavy rain.
The growing international concern about the situation in western Sudan has led to calls for a limited form of military intervention.
"The Security Council resolution about the Darfur issue is a declaration of war on the Sudan and its people," armed forces spokesman General Mohamed Beshir Suleiman told the official Al Anbaa daily newspaper.
"The Sudanese army is now prepared to confront the enemies of the Sudan on land, sea and air," he said.
"The door of the jihad is still open and if it has been closed in the south it will be opened in Darfur," he said, referring to a peace deal to end 20 years of war in southern Sudan.
Nigeria's President Olusegun Obasanjo visited the Sudan capital, Khartoum and Libya over the weekend seeking an "African solution" to the crisis.
As chairman of the African Union, he is pressing for African troops to be sent to Darfur to disarm the Janjaweed, and the two rebels groups, accused by Sudan of starting the conflict by taking up arms last year.
Nigeria, South Africa and Rwanda had promised to send 300 soldiers to Darfur by the end of July but these have not yet arrived.
France is deploying 200 soldiers to secure Chad's eastern border with the Darfur region and deliver humanitarian aid to the 200,000 Sudanese refugees in Chad.
France has about 1,000 troops in Chad, who until now have been helping to promote stability and train Chadian forces for peacekeeping duties.
Up to 50,000 people have died since the conflict began in early 2003.
Darfur has been described as the world's worst humanitarian crisis
Refugees say the Janjaweed follow up government air-raids by riding into their villages, slaughtering the men, raping the women and looting.
The US-drafted resolution demands that Sudan make good on promises it made on 3 July to rein in the fighters.
It calls for UN Secretary General Kofi Annan to issue a report in 30 days on the progress made.
But Sudan said that this promise it made to Mr Annan gave it 90 days to stop the violence.
A cabinet statement also criticised the resolution for not blaming the rebels, who "took up arms and therefore... bear the responsibility for all the human and security tragedy in Darfur".
The resolution was only adopted after the US dropped the word "sanctions" and added economic and diplomatic "measures".