A senior U.S. official is heading to Darfur, Sudan, for talks with rebel leaders in an effort to move peace efforts forward. Assistant Secretary for African Affairs, Jendayi Frazer, discussed her trip at a hearing before the U.S. Congress.

Just hours before her departure for Darfur, Ms. Frazer told a Senate Foreign Relations subcommittee she plans to meet with rebel leaders to urge them to overcome their divisions and present a united front at peace talks in Abuja, Nigera.

Previous rounds of talks in Abuja have been plagued by delays and have made little progress, amid escalating violence in Darfur.

Still, Assistant Secretary Frazer says negotiations are the only way to bring peace to the troubled region. "The most important front is to try to get a political solution. That is ultimately what will allow people to go home, to return home, to create an environment of peace and safety and security through a political negotiation," she said.

Some 7,000 African Union peacekeepers are in Darfur, where fighting between rebels and government-backed Arab militia has killed tens of thousands of people over the past two years, and left two million homeless.

Ms. Frazer says 12,000 peacekeepers are needed, and consultations are under way with the A.U. to expand the size of the force.

She called on the A.U. to clarify its mission in Darfur, saying peacekeepers have not done enough to safeguard civilians. "The AU mandate is quite clear. They do have the capacity under their mandate to protect civilians, but that that word has not gotten out to the units uniformly. So part of it is to absolutely clarifying that mandate to the various units," she said.

Senator Barack Obama, an Illinois Democrat, said he believes the Bush administration could be doing more to end the Darfur conflict. "I am getting a sense of drift right now in terms of the policy in Darfur. My hope would be that we start ramping up activity, including putting more pressure on other countries to get involved in this issue, because right now we have got an enormous number of people, who have for the past year or year and a half, have been living in camps, and there is a crisis that is going to explode if we do not catch it now," he said.

Assistant Secretary Frazer says the administration does have a sense of urgency about the situation in Darfur. "I can assure you this is getting the highest level of attention from President Bush, Secretary (of State Condoleezza) Rice, Deputy Secretary (Robert) Zoellick, myself and others," she said.

Ms. Frazer noted she is making her third trip to Darfur in a month, while Deputy Secretary Robert Zoellick has also been holding talks with rebels and the government this month.

The United States has called the Darfur violence genocide, a charge the Sudanese government denies. The International Criminal Court is investigating war crimes in the region.