Human Rights Watch has released a major study on the growing humanitarian crisis in the Darfur region of western Sudan, charging that Janjaweed militiamen, armed and backed by the Sudanese army, had mounted attacks against African tribal villages in a war of "ethnic cleansing."

The group based its documentary evidence on a trip by former foreign correspondent Julie Flint, who interviewed scores of Sudanese survivors and refugees along the Chadian border between March 17 and April 21, visiting villages in the Masalit area of Darfur by foot and on horseback.

During 25 days in the region, Flint said, she encountered only "a dozen or so civilians, walking skeletons, braving hazardous journeys for miles to dig up food they had buried three meters deep."

She chronicled and registered the deaths in 14 villages based on interviews with survivors, saying the majority of victims from the Masalit area she documented were men.

Flint, 56, a British journalist and fluent Arabic speaker, has worked for Le Monde, the Guardian, the Observer and ABC Radio since 1970, spending many years in the Middle East.

She said she gradually branched into humanitarian research and investigative documentary film projects in the early 1990s, traveling to Turkey, Colombia and China, as well as Sudan, to focus on human rights violations.

Flint's research for Human Rights Watch, a New York-based organization, is the basis of a report entitled "Darfur Destroyed." It describes the Sudanese government's use of "attack aircraft, mainly Antonov supply planes dropping crude but lethal 'barrel bombs' filled with metal shards, but also helicopter gunships and MiG jet fighters in areas inhabited by . . . farmer tribes that have been chased off their land."

Recording the names of villagers killed or wounded, locations and dates, Flint quoted witnesses describing how hundreds of people, including women and children, were killed in their homes.

In some villages in Darfur, she reported, men were rounded up, forced to kneel, then shot in the back. She said that in one such mass execution on March 5, 145 men were killed. They were members of the Fur tribe in Wadi Saleh, a province of West Darfur state.

"From mid-2003, attacks on villages rather than rebel positions have been the norm rather than the exception," Flint wrote. She said many villages had been razed to the ground, including the clay foundations of small houses.

"Today's farmer is tomorrow's rebel, today's displaced is tomorrow's rebel," she said of the conflict in Darfur, fueled by racial and ethnic sensitivities and based on claims to that region's natural resources by the central government.

She said the rebels could not match the government's firepower, instead using horses, Kalashnikov assault rifles, grenades and rocket-propelled grenades, but they have no artillery, planes or tanks like the government-armed militias fighting them.

"These are not attacks by militias, but by government militias," Flint said. "Government troops have bombed towns that had fallen under their control such as Habila, because thousands of displaced farmers had fled there from the bombardment."

One lawyer accompanying her said he had lost nine members of his family in Habila, a town he said government troops bombed six times in one day.

Flint carried a video camera on the trip and said she was inspired to switch from daily journalism by the desire to spend more time on her subject. "This work is not about a byline," she said. "It's not politics, it's people."

Minky Worden, the electronic media director for Human Rights Watch, said at a news briefing that the Sudanese government is "receptive to political pressure at this time." The human rights organization said it was pushing for a link between disarming the Janjaweed militia, which it has documented working alongside the Sudanese army, and the return of people to their homes.

Worden said the government allowed relief groups to enter certain affected areas of Darfur this week, as a result of recent pressure from the United Nations. Still, a spokesman for the U.N. Children's Fund described the situation as "a race against time," with reports of children dying of hunger and thirst.

Human rights groups and other international agencies have estimated that more than 1 million people may be displaced in the Darfur region and have warned that 350,000 people could die from starvation, dehydration and disease.

In a tentative resolution of another Sudanese dispute, representatives of the Khartoum government and Christian and animist rebels reached an agreement toward ending a civil war in the country's south.

Jemera Rone, a lawyer and researcher for Human Rights Watch, said in a telephone interview that the pact is expected to lead to a full cease-fire that would end 21 years of civil conflict in which more than 2 million people have died because of famine and war.

She said the pact calls for the application of Islamic law in the capital, Khartoum, adding that guarantees are needed to ensure protection for non-Muslims there.

Julie Flint traveled for 25 days on foot and horseback in the Darfur region of Sudan to collect evidence of attacks by government-backed militiamen.