Human rights group Amnesty International said Tuesday it believes that Russia and China are supplying weapons to Sudan in violation of a United Nations arms embargo.

Amnesty International, in a new report on Sudan, said it is "deeply dismayed"that the weapons are being diverted for use in Sudan's troubled Darfur region and neighbouring Chad.

The Arab militia known as the Janjaweed is using the imported weapons, it added.

"States supplying weapons, munitions and other military equipment to Sudan and to other parties to the conflict know, or at least should know, that these arms are often used to commit serious violations of human rights and international humanitarian law in Darfur and now in eastern Chad," the report reads.

"Governments that ratify international human rights treaties have a particular obligation to ensure that such treaties are upheld and that the human rights of the population living within the state are protected," it says in its conclusion.

China rejected the report on Tuesday, with Chinese Foreign Ministry spokeswoman Jiang Yu saying the accusations were "groundless." She saidits exportstoSudan were limited and small in scale.

The United Nations estimates more than 200,000 people have died through killings, illness and starvation since the conflict began four years ago between militias and rebel groups in Darfur.

More than two million people have been forced to flee their homes. Those in refugee camps complain that they are still threatened by the government-backed Janjaweed. There are 7,000 African Union peacekeepers in Darfur, but they have been unable to stop the violence.

Brian Wood, one of the authors of the report, called on Russia and China to comply with the UN embargo to protect civilians in Darfur.

"We are talking about the worst humanitarian catastrophe on the planet," Wood told CBC News on Monday.

"Both the governments of the People's Republic of China and the Russian Federation need to rein in all of their arms supplies and munitions supplies to Sudan as part of a package of measures needed to help get the human rights of people of Darfur back again."

The report said Sudan, according to its latest available trade figures, imported at least $24 million in arms, ammunition, parts and aircraft equipment, helicopters and airplanes from China in 2005 and at least $21 million in aircraft, spare parts and helicopters from Russia in 2005.

It said Kuwait, Saudi Arabia and Belarus have also been supplying arms to Sudan.

Larger implications for UN

Amnesty said in the report that China and Russia are well aware of how their weapons are being used in Sudan and theongoingflow of weaponshas larger implications for the UN.

"The authority of the Security Council itself is being greatly undermined as the Sudanese authorities and armed groups in Darfur are allowed to act with such obvious impunity before the eyes of the world, importing and diverting arms to commit flagrant violations of international law," Amnesty said.

In July 2004, the UN Security Council imposed an arms embargo on non-governmental groups in Darfur. In March 2005, that embargo was extended all parties in the conflict.

Amnesty said the embargo is "somewhat vaguely formulated" and lacks a mechanism by which the UN can monitor, verify and publicly report on compliance, which means some states are able to violate it with impunity.

It called the UN to strengthen the embargo.