A leading human-rights group has accused high-ranking Sudanese government officials of committing crimes against humanity in the Darfur region of western Sudan, and has called for the officials to be investigated. 

Human Rights Watch released an 85-page report documenting the role of high-ranking Sudanese civilian and military officials in a conflict the U.S. government calls genocide. 

The report alleges that Sudan's government supplies and supports the Janjaweed, a militia believed to cause much of the human rights violations in the region.

It also accuses the Sudanese army of attacking civilians and turning a blind eye when atrocities are taking place.

One of the report's authors, Leslie Lefkow, tells VOA that senior government officials, including president Omer al Bashir, must be held accountable for the situation in Darfur.

"It is clearer than ever that the policy of the Sudanese government in Darfur was extremely well structured, was extremely methodical, systematic in attacks on civilians and that top senior leadership certainly knew or should have known what was happening and certainly have done nothing to prevent or punish these crimes," said Leslie Lefkow.

But human rights activists say that prior reports have detailed the involvement of the Sudanese government and say nothing has been done.

Dr. Mudawi Ibrahim heads the largest Sudanese aid organization operating in Darfur.  He says the reports are not enough to prevent the Sudanese government from acting with impunity in the region.

"This has been said a lot of times," said Dr. Mudawi.  "And also sometimes it has been admitted by the government themselves.  They are not denying the bombardment.  They are saying we have been bombarding villages because the rebels are using the villages.  They have never denied this.  We have to move actually.  It is not only reports; we have to move."

Mr. Mudawi says the International Criminal Court must indict suspected war criminals immediately.

The Hague-based court, set up several years ago to investigate war crimes, was asked by the U.N. Security Council early this year to investigate crimes against humanity in Darfur.

The Sudanese government, which has long denied supporting the Janjaweed militias, spurned the international court and vowed to prosecute war criminals internally.  The Human Rights Watch report labels those efforts a façade and denounces what it calls sham prosecutions.

The Darfur conflict has raged since 2003 when the rebels rose up to protest what they say is political, economic, social, and racial repression from the government.

An estimated 180,000 people have been killed and more than two million displaced by the conflict.

The report urges the United Nations to impose sanctions against those responsible for the atrocities.  These include freezing assets and issuing travel bans.

The report was released one day before the International Criminal Court's lead prosecutor on Darfur, Luis Moreno Ocampo, will address the U.N. Security Council about possible indictments.