Meanwhile, Secretary of State Colin Powell said he is "completely dissatisfied" with the security situation in Darfur, an expanse of desert along Sudan's 370-mile border with Chad. He acknowledged some marginal improvements in the humanitarian situation there in recent weeks.
The United States has been pushing for a U.N. Security Council resolution that could impose sanctions against the Sudanese government, accused of supporting Arab militias blamed for atrocities against the black African population.
Sudanese Foreign Minister Mustafa Osman Ismail (search) has warned that any U.N. action would only complicate efforts to resolve the situation.
A U.S. draft resolution demands that Sudan immediately fulfill all its commitments to end violence in Darfur and to give access to aid workers.
It also urges the Sudanese to conclude a political agreement without delay, and it commits all states to target sanctions against the government-backed militias held responsible for the crisis.
With more than 1.2 million Darfur residents displaced and tens of thousands killed, independent analysts are seeking a U.S. declaration that the atrocities meet the legal definition of genocide as outlined in a 1946 international agreement.
The dictionary defines genocide as "the systematic killing of a racial or cultural group."
State Department spokesman Richard Boucher said Tuesday U.S. officials have been interviewing Sudanese refugees who have crossed the border into Chad.
He said 50 have been interviewed thus far with 1,000 or more to go.
"We'll be reviewing it from a legal point of view to see if at some point that evidence constitutes evidence of genocide," Boucher said.
But, he said, the first priority is to stop the violence and to meet the humanitarian needs of the people.
Boucher added that enough information may emerge from the initial stages of the interviews to make a determination on whether genocide has taken place.
Under the Genocide Convention, any member state "may call upon the competent organs of the U.N. to take such action under the Charter of the U.N. as they consider appropriate for the prevention and suppression of acts of genocide."
Powell said not enough is being done to break the hold of the militias responsible for the suffering in Darfur.
"Rapes are still occurring," he said. "People do not feel safe leaving the camps to go out and forage for food. The situation remains very, very serious, and first and foremost, the security has to be dealt with."