Amnesty International says it has photographs that prove the Sudanese government continues to deploy military equipment in Darfur in "breathtaking defiance" of a UN arms embargo.

The human rights group is calling for the UN Security Council to act on the information by ensuring the embargo is enforced and placing UN observers at all ports of entry in Sudan and Darfur.

The photographs were said to have been taken by an eyewitness in July and show containers being offloaded at the army airport in the West Darfur state capital of El Geneina.

Sudanese officials told the BBC that the photographs are suspect.

One of the three pictures released Thursday shows an Antonov freight aircraft that Amnesty officials said was supplied by Russia and registered to Azza Transport, a Sudan-based airline under investigation by the UN Panel of Experts for arms transfers.

"The Sudanese government is still deploying weapons into Darfur in breathtaking defiance of the UN arms embargo and Darfur peace agreements," Brian Wood, Amnesty International's arms control research manager, said in a news release. "Once again Amnesty International calls on the UN Security Council to act decisively to ensure the embargo is effectively enforced."

Brian Wood, a military expert at Amnesty's London offices, said that while there is no way of knowing what was in the photographed containers, the military aircraft shown in the photographs had arrived from Sudan's capital on flights that were not reported to or permitted by the UN.

"And that means that those are violations of the Security Council arms embargo to Darfur," Wood told the Associated Press by telephone. "We have indicated that we know of similar flights with small arms and weapons to militia and armed groups that have attacked civilians in the past."

In 2005, the UN Security Council imposed an arms embargo on all parties involved with the conflict in Darfur.

An estimated 200,000 people have died from killings, illness and starvation since the conflict began four years ago, the United Nations says. More than two million have been forced to flee their homes.

The conflict dates back to 2003 when predominantly Muslim militants began attacking government forces in the western region of Darfur, accusing the Arab-dominated central government of discrimination.

Sudan is accused of retaliating by unleashing Arab militias, which are blamed for war crimes against civilians.