The Sudanese government has been accused of carrying out at least 30 gas attacks in Darfur which are feared to have killed hundreds of children.
Amnesty International says it has obtained video and photo evidence which shows Sudanese civilians dying in agony as they vomit blood and struggle to breathe following a spate of chemical attacks in the war-torn region.
Its report estimates that up to 250 people have died in the Jebel Marra area of Darfur since January, and that the majority of them are children.
The Telegraph attempted to reach the Sudanese government for comment at its embassy in London on Wednesday, but did not receive a response.
Darfur is in the grip of a civil war which has seen more than 300,000 people killed since the conflict began in 2003.
Omar al-Bashir, the Sudanese president, has been accused of leading a campaign of rape and mass murder against civilians in Darfur – the International Crime Court (ICC) charged him with genocide in 2008.
Amnesty International says it carried out interviews with survivors who claimed bombs containing “toxic smoke” were dropped in their villages.
Chemical weapons experts told the charity they suspected the bombs contained blister agents such as mustard gas as the bombs were reported to have changed colour after being detonated.
Those who survived the initial bombings went on to develop skin blisters, chronic diarrhoea, bloody vomiting and in some cases total loss of vision.
One 20-year-old survivor interviewed by Amnesty International said she and her baby fell sick six months after escaping one of the attacks and are yet to have recovered.
“When the bomb landed there were flames and dark smoke,” she said.
“Immediately it caused vomiting and dizzying. My skin is not normal, I have headaches. The baby is not recovering, he is swollen, he has blisters and wounds.”
Tirana Hassan, Amnesty International’s director of crisis research, said: “The scale and brutality of these attacks is hard to put into words.
“The images and videos we have seen in the course of our research are truly shocking; in one a young child is screaming with pain before dying; many photos show young children covered in lesions and blisters. Some were unable to breath and vomiting blood.”
She added: “The fact that Sudan’s government is now repeatedly using these weapons against their own people simply cannot be ignored and demands action.
“These are the same war crimes being committed in Darfur as in 2004 when the world first woke up to what was happening.”
The human rights charity said it has also seen satellite images which confirmed that 171 villages in the South Sudan have been “damaged or destroyed” in the attacks.