Clambering onto donated sacks of grain, Sudanese refugees strained Wednesday for a look at Secretary of State Colin Powell (search), who came to tour camps and press the government to end ethnic violence and a humanitarian crisis he has called "catastrophic."

Powell's visit came as the United States increased pressure on Sudan (search) with a draft resolution calling on the United Nations to impose an arms embargo and travel ban on the Arab militias that are blamed for attacks in Sudan's western Darfur region.

Powell and U.N. Secretary-General Kofi Annan (search) met in Khartoum during a rare coordinated visit aimed at making sure the crisis that has forced more than 1 million people to flee their homes and killed 30,000 over the last 16 months is not ignored as Rwandan killings were a decade ago.

Annan, meeting with Sudanese officials, said urgent action was needed and that he hoped "to make some real progress in the next 24 to 48 hours."

The United Nations has called the situation in Darfur the world's most serious humanitarian crisis. Powell has described it as "horrific" and "catastrophic."

But those assessments are sharply disputed by the Sudanese government. Sudanese Foreign Minister Mustafa Osman Ismail, who accompanied Powell to Darfur, said Tuesday night that "there is no famine, no malnutrition and no disease."

And Powell told National Public Radio afterward that the situation "doesn't meet the tests of the definition of genocide."

"I can assure you that if all the indicators lined up and said this meets what the treaty test of genocide is, I would have no reluctance to call it that," Powell said.

He said he told President Omar El-Bashir that "the first thing that must be done is to break the back" of the militias that have driven people out of their homes in Darfur.

In 100-degree temperatures, Powell walked through the dusty Abu-Shouk camp as thousands of sometimes raucous refugees watched, some climbing atop a pile of U.S. donated sacks of a corn-soy blend and wheat to get a better view.

Other than the rows of fragile, makeshift shelters built mostly with plastic sheeting, there was no overt display of serious humanitarian need among those Powell saw. Earlier this week, Powell had raised the possibility that Sudanese authorities might try to mask the gravity of the situation by emptying refugee camps in time for his visit.

He noted after the visit that the refugees he saw appeared less needy than those housed elsewhere.

Powell spent much of his time during his brief visit at Abu-Shouk conferring with an official from the International Committee of the Red Cross. He also met with an international team attempting to monitor a cease-fire between rival factions in Darfur and U.S. and U.N. aid representatives.

Several people told reporters accompanying Powell about relatives killed by the Janjaweed militias — Arab groups that have carried out a brutal counterinsurgency against black African rebels, displacing an estimated 1.2 million people.

Powell has given high priority to a political settlement. He expressed satisfaction with Ismail's comments but indicated that it was too early to say a corner had been turned.

After his brief tour of the camp, Powell said that the people there are "being given hope as well as sustenance. We don't want them to stay in camps. We all want them to return to their homes." But, he said, people cannot be expected to be returned until security is established.

Only rarely do secretaries of state visit countries on the official U.S. list of state sponsors of terrorism. Sudan is on that list though the Bush administration has praised the government for sharing intelligence on terrorist groups. Except for food and medicine, the United States bars trade with Sudan.

The crisis in Darfur is not directly related to the 21-year war between the Islamic government in Khartoum and the mostly non-Muslim population in the southern part of the country.

With the help of U.S., African and other mediators, the two sides have taken strides toward ending that conflict.

But Powell has said that so long as the Sudanese government does not take decisive steps to cut its ties to the Arab militias, Sudan cannot expect to have normal relations with the United States. In remarks Tuesday night, Powell warned that Sudan could face U.N. Security Council action if it fails to rein in the Arab militias.

Human rights groups have accused the Sudanese government of backing militias drawn from Arab herders in a campaign to forcibly remove African farmers from the region. Claiming that atrocities were being carried out with the "full cooperation" of the government, student protesters clashed with riot police Wednesday in the Sudanese capital.

Powell left Khartoum at sunset for Indonesia, where he will meet with Pacific Rim leaders. He is expected back in Washington early Sunday morning.