KHARTOUM — Sudan on Saturday strongly criticised the United States for intentionally distorting and damaging the country's image, and urged the US State Department not to be a "tool of war."

"We call on activists in the US Congress committees and in US foreign policy-making institutions, led by the ministry of foreign affairs, to help in consolidating peace and stability in Sudan, and to not be a tool of war," the Sudanese foreign ministry said in a statement.

The statement came after separate accusations in Washington on Friday, by US Secretary of State Hillary Clinton and senior US lawmaker Chris Smith, about Khartoum's actions in the volatile Sudanese border regions of Abyei and South Kordofan.

Smith, who heads the House Foreign Affairs sub-committee on Africa, said there were credible signs of systematic attacks by the Sudanese army against the indigenous non-Arab Nuba people.

He urged the immediate deployment of peacekeepers, warning of a risk of "genocide" by government forces.

Sudan's foreign ministry dismissed the claims.

"The military operations carried out by the Sudanese authorities in South Kordofan target the rebels, regardless of race, colour, religion, and attempts to portray this as targeting the Nuba peoples... are deliberate attempts to distort and damage Sudan's image," it said.

Fighting has raged in the ethnically divided border state since early June between the Sudanese army and Nuba militiamen, who fought with the SPLA, the former rebel army of the south, during their 22-year civil war with Khartoum.

Clinton, meanwhile, said on Friday that she was "alarmed" that the Sudanese authorities may have delayed the evacuation of UN peacekeepers who were fatally wounded in a landmine blast in the disputed Abyei region earlier this week.

Sudan has already rejected charges that it purposely obstructed a UN helicopter evacuation of the Ethiopian peacekeepers, three of whom died several hours after the incident, insisting it acted in the shortest time possible.

On Saturday, the foreign ministry said Clinton's comments were linked to "hostile activities" within certain decision-making institutions in the US that were intent on destroying the reputation of Sudan and weakening the country, "to benefit the agenda of interest groups."

Khartoum has sought better relations with the United States, including the lifting of sanctions.

But it insists that South Kordofan is a domestic issue and has made clear its opposition to any new peacekeeping force since the previous UN mission's mandate expired last month.