Secretary of State Condoleezza Rice on Wednesday defended the Bush administration's response to the ethnic violence in Sudan's Darfur region, saying U.S. actions have helped "avert some of the humanitarian disaster that was foreseen" a year ago. She also said U.S. leadership was critical to a rapid buildup of African Union peacekeeping forces now underway, which she said showed that Africa was taking a leading role.

"We have worked hard," Rice told reporters in Dakar, the capital of Senegal, before flying to Sudan's capital, Khartoum. She will hold talks with Sudanese officials Thursday before flying to Darfur to tour a camp known as Abu Shouk, which houses about 70,000 displaced people. Her predecessor, Colin L. Powell, visited the same camp a year ago when it was about half that size.

But Sengalese Foreign Minister Cheikh Gadio, standing next to Rice, said the response by the African Union and other countries to the political violence and humanitarian crisis in Darfur had been inadequate.

"We went from 70,000 dead, we were told, to over 200,000 dead," he said, referring to the situation a year ago. "We were told 900,000 displaced; now we are told 2 million displaced. This is just not acceptable."

About 1.8 million people live in more than 100 camps in Sudan, with another 200,000 in camps across the border in Chad. Tens of thousands more have died in the Darfur conflict, which broke out in early 2003 when two largely black African rebel groups attacked police and military posts. The United Nations accuses the Arab-led government of supporting militias, called the Janjaweed, and bombing villages to crush the rebellion.

Estimates of the dead from the conflict range as high as 400,000, although the State Department has put the number much lower, between 63,000 and 146,000. On Wednesday, Rice reiterated the administration's view that genocide has taken place in Sudan; the U.N. Security Council has authorized the International Criminal Court to conduct a war crimes probe.

Sudanese officials "are still very actively killing people, burning villages, raping women," Gadio said, calling the situation "totally unacceptable." He said "we all should come together in a new way in dealing with the suffering of the people of Darfur."

Rice's deputy, Robert B. Zoellick, has traveled to Sudan three times in the last three months, visiting camps in different areas of Darfur and crisscrossing the country to encourage the implementation of a peace agreement resolving an unrelated conflict in southern Sudan. In an upbeat appraisal this month, Zoellick said "a fragile equilibrium" had been achieved in Darfur. He said the militias were not conducting attacks and the Sudanese military had pulled back, although he acknowledged part of the reason was because so many people had fled to camps.

Andrew Natsios, head of the U.S. Agency for International Development, told reporters traveling with Rice that the death rate in Darfur had dropped below one per day per 1,000 people -- the level considered a crisis. But malnutrition rates remain high, he said, adding that the United States has spent $700 million on humanitarian aid in Darfur.

But Eric Reeves, a professor at Smith College in Massachusetts who closely studies Sudan's many conflicts, issued a lengthy analysis last week in which he said reports of improvement in Darfur are "expedient nonsense." He said that the violence by the militias and Khartoum's military had not halted and that the threat of violence had made growing crops impossible. He also said the U.N. decision to refer the issue to the International Criminal Court had led to increased attacks on humanitarian workers.

The African Union is building up a force of 7,700 troops in Darfur, up from 2,700 this year, with many troops being flown there through the assistance of NATO and the European Union. U.S. forces plan to airlift 300 Rwandan troops into Darfur as Rice begins her visit Thursday.

Rice said sending the additional troops was an "important step forward" because "when there is monitoring there is less violence." The troops, however, have no mandate to thwart potential attacks, only to report on the situation; Natsios said they are accompanying women when they forage for firewood in order to prevent rapes.

Rice also credited U.S. involvement in a recently implemented peace agreement that ended a two-decade civil war between the northern and southern parts of Africa's largest country. She said the deal -- which this month brought former rebel leader John Garang into the government as first vice president -- provides a framework for resolving the unrelated Darfur conflict.

"This is a new government, and I will start from the point that it could also be a new day," she said.

The Sudanese government has repeatedly presented plans to deal with the conflict, but it appears to have taken few steps beyond ending military support flights in February.

"We don't rely on words," Rice said. "We rely on actions."

Secretary of State Condoleezza Rice listens to a question at a news conference in Senegal's capital, Dakar. She was to fly to Khartoum for talks with Sudanese officials and visit a refugee camp in Darfur, Sudan's troubled western region.