The research and a forthcoming report by the World Health Organisation on the same issue will renew international attention on the siege of Fallujah, condemned by anti-war activists and human rights campaigners as an excessive response to insurgent activity. Thousands of alleged insurgents and civilians are said to have been killed. White phosphorous and depleted uranium shells are known to have been used in large numbers. Depleted uranium in particular has been linked to high rates of cancer and birth defects.