Satellite photos of the Darfur region of western Sudan (search) show destruction in nearly 400 villages, and there have been reports of fighting or threatened attacks in every camp for displaced people, the U.S. aid chief said.

Andrew Natsios, administrator of the Agency for International Development (search), warned that time is running out to help 2 million Sudanese in desperate need of aid in Darfur. He said his agency's estimate that 350,000 could die of disease and malnutrition over the next nine months "is conservative."

Fighting between Arab militias and African residents has killed thousands of people and forced more than 1 million to flee their homes. International rights groups say the government has backed the Arab fighters in an ethnic cleansing campaign against the African villagers.

Natsios put the blame for the crisis squarely on the Sudanese government, saying U.S. and U.N. reports from the country show clearly that the Sudanese military is directly connected to Arab militias, known as the Janjaweed, that are fighting in Darfur.

"They arm them, they use them, and now they have to stop them," Natsios said in an interview Wednesday with two reporters after meeting with U.N. Secretary-General Kofi Annan (search). Annan is planning to visit Sudan soon and assess the situation in Darfur.

Last week, Annan said the United Nations had asked the Sudanese government to take steps to contain the Janjaweed. The government denies any complicity in the militia attacks against the black African population, blaming the trouble in Darfur on rebels and criminal gangs, but Annan said "from all accounts they can do something about the Janjaweed."

Natsios said that despite frequent Sudanese government announcements about "all the things they've done to improve things," virtually nothing has changed on the ground.

The latest weekly assessment of conditions in the 36 camps for displaced people in Darfur showed that in every one, security was poor and those taking refuge faced attacks or threats of attacks, Natsios said. He did not say who ran the camps.

"They've got to stop stonewalling the relief effort," Natsios said of the government. "What they need to do is enforce the agreement they signed" in neighboring Chad on April 8 to allow humanitarian agencies into the area.

Fighting erupted in February 2003 when African tribes in Darfur rebelled against what they regarded as unjust treatment by the Sudanese government in their struggle over land and resources with Arab countrymen.

USAID released updated figures Thursday saying satellite photos of 578 villages in the Darfur region found that 301 were destroyed, 76 damaged and 199 intact. Two were determined to be old ruins.

The U.S. agency also obtained photographs of 87 villages in neighboring Chad, in the area bordering Darfur, and reported that eight were destroyed, 24 damaged and 55 not damaged. More than 100,000 refugees from western Sudan have fled across the border into Chad.

"When we checked them on the ground, we confirmed what we found," Natsios said. "We are going to watch them, using aerial photography for the duration to track what's happening."

On Saturday, Sudanese President Omar el-Bashir ordered the military to begin disarming all militia groups. But Ambassador Michael Ranneberger, a U.S. State Department expert on Sudan, said "until now, we have not seen any systematic action to rein in the Janjaweed."

"What we've seen is a series of half-steps by the government in response to international pressure," he said.

U.S. officials have been highlighting the plight of the displaced Sudanese, mindful that the world's inattention to Rwanda a decade ago may have contributed to the genocide that occurred there.

Natsios said the U.S. government has spent $116 million on the relief effort in Sudan -- more than all other donors combined -- "and we pledged $188 million between now and the end of next year."

Natsios said USAID had NASA take aerial photographs of the destruction of the villages. But a USAID spokeswoman issued a clarification Thursday, saying the agency's analyses were based on photos from commercial satellite imagery.

The United States is moving "with a maximum sense of urgency to try to save lives," said Ranneberger, who accompanied Natsios. "We don't have time to sit around also and decide, is this ethnic cleansing or is this genocide, or what is it."

Natsios said President Bush has made clear to Bashir that U.S.-Sudanese relations will not be normalized "until these atrocities are stopped and until all impediments to the relief effort are ended."