An international human rights group says it has proof that the Sudanese government is supporting and even helping to arm the Arab militias, known as Janjaweed, that have killed tens of thousands of people and displaced close to a million others in the Darfur region of Sudan.

Human Rights Watch says it has obtained four government documents that show the Sudanese government helped recruit militiamen, armed them and took steps to overlook the mass murders and rapes the Janjaweed fighters have allegedly committed against black Sudanese residents.

Government officials in Sudan have long denied any links to the Janjaweed militia. The head of Human Rights Watch, Kenneth Roth, says his group now has papers that prove otherwise.

"What we have today are insider documents, official documents of the Sudanese government that confirm this official support of the Janjaweed militia as a matter of policy," he said.

Mr. Roth says a series of documents dating from November 2003 to March 2004 detail the Sudanese government's support of the Arab militias.

In one of the documents, Mr. Roth says the mayor of a locality within Khartoum province ordered local security units to grant access and supplies to a Janjaweed militia leader known as Sheik Musa Hilal.

"In this document, the mayor urges these local security officials to "permit the activities of the mujahedeen and volunteers under the command of Sheik Musa Hilal to proceed in the area and to secure their vital needs," he said.

Human Rights Watch says it has received the documents from what it calls a credible source whose information has been corroborated in the past. Meanwhile, another human rights group, Amnesty International, accused Arab fighters of using rape as a weapon against black villagers.

Sudanese officials in Khartoum have pledged to protect residents, but a U.N. spokesman said Monday little progress has been made in assuring security, although access to humanitarian aid has improved.

The U.N.'s top envoy to Sudan, Jan Pronk, will brief the Security Council later this week about the most recent developments in what some observers are calling the world's worst humanitarian crisis. The Security Council is deliberating a resolution to place an arms embargo on Sudan.