The attack on civilians was reminiscent of the early years of the counter-insurgency operation in Sudan's west, which took up arms against the government in 2003, complaining that the region had been neglected by Khartoum
The International Criminal Court in The Hague has since issued an arrest warrant for Sudanese President Omar Hassan Al-Bashir for genocide and war crimes in Darfur, charges he denies.
Details of the Sept. 2 attack on the market in the village of Tabarat have not previously come to light. The government prevented peacekeepers from visiting the site until days later.
But five survivors of the attack told Reuters that heavily armed Arab militia had targeted male victims and shot many at point blank range.
One diplomat said the militia were likely from among those armed and mobilised by the government to quell the rebels. Those militia, known as Janjaweed, were responsible for mass rape, murder and looting. Many of the tribal militia still support the government but Khartoum has lost control over some.
In Tabarat, men were rounded up by militia wearing military uniforms who rode into the market on horses and camels pretending to be buying goods before spraying the shops with gunfire. Then vehicles mounted with machine guns and carrying militia fighters appeared and rounded up some of the men, survivors said.
"They laid them down and they came up close and shot them in their heads," Abakr Abdelkarim, 45, told Reuters by telephone from the town of Tawilla, where many of the victims had sought refuge and medical help.
"(Those killed) were all men and one woman — some men were tied with rope behind the cars and dragged until they died."
Adam Saleh said he had run for his life and hidden in nearby fields to watch from afar. "They were targeting men — all of them were shot in the head and chest, only those who were running away got shot in their legs and arms."
Nour Abdallah, 45, said the attackers let most of the women run away. She could not escape and so lay face down in the dirt. "They told me not to lift my head up or I would be shot too."
Saleh and others said after the attack they had gone to the joint UN-African Union (UNAMID) peacekeeping base in Tawilla to ask peacekeepers to come to Tabarat but they had refused.
"They also refused to come and help us recover the bodies," Saleh added.
UNAMID has said both rebels and the government prevented it getting access to the area.
A UNAMID spokesman said he could not comment on the witness reports but an internal document seen by Reuters showed UNAMID had received similar witness reports of men being executed.
The only aid agency working in Tawilla, Medecins Sans Frontieres, said it could confirm 39 people died and it had treated 46 injured, many with "serious gunshot wounds."
"We saw only men," said MSF head of mission Alessandro Tuzza. He said he could not comment on how the victims were shot but that MSF was still negotiating with the government to get access to the area in North Darfur province.
The witnesses said they had buried 41 bodies in common graves but more were still in the bushes around the market.
Sudan's army denied involvement in the attack and said the local government was investigating. "The North Darfur government have formed a security committee to investigate this."
Presidential adviser Ghazi Salaheddin visited the area on Friday on a fact-finding mission.
Kidnapping and violent banditry have become frequent in Darfur where years of impunity and the ready availability of arms have fueled a breakdown in law and order, with foreign workers targeted for abductions even in the main towns.
Bashir expelled 13 of the largest aid agencies working in Darfur after the ICC arrest warrant last year and many gaps in the humanitarian operation have yet to be filled.
"We are begging the international aid agencies to come and give us food, water. We have women and children here sitting in the sun for days with no shelter. We have nothing," said Abdelkarim.
