New research is underway on the alarming increase in birth defects in the Iraqi city of Fallujah.
In November 2004, the US led an assault on Fallujah - a stronghold of opposition against the US occupation, west of Baghdad. Intense bombardment left many of its buildings destroyed and displaced much of the 300,000-strong population.
Eventually, the US was forced to admit that amongst its arsenal was white phosphorus - a substance the Pentagon described as a 'chemical weapon' when it was used by Saddam Hussein against the Kurds.
In addition, eyewitnesses claimed the US military used "unusual weapons".
Subsequent investigations have focused on the possible use of depleted uranium by the US for its armour-piercing qualities. The US, however, denies using such weaponry.
Research has shown elevated levels of radioactivity in Fallujah and across Iraq.
Iraqi physicians have also long reported a spike in cases involving severe birth defects in Fallujah since 2004. They have reported children born with multiple heads, serious brain damage, missing limbs and with extra fingers and toes.
A report published in 2011 on the level of uranium and other contaminants in hair from the parents of children with congenital anomalies in Fallujah partly concluded that: "Whilst caution must be exercised about ruling out other possibilities, because none of the elements found in excess are reported to cause congenital diseases and cancer except uranium, these findings suggest the enriched uranium exposure is either a primary cause or related to the cause of the congenital anomaly and cancer increases. Questions are thus raised about the characteristics and composition of weapons now being deployed in modern battlefields."
Al Jazeera's Sebastian Walker reporting for the programme Fault Lines examined the legacy of the US occupation in Iraq and described what he saw on a road trip across Iraq after the withdrawal of US troops.
"What we found by visiting the general hospital there is that there are extremely high rates of birth defects, some five times the international norm, and many of the doctors who work in those hospitals believe that this is a direct result of the kind of weapons the US forces were using in those campaigns."
Many researchers say uranium from the shelling may be to blame. However, no conclusive proof of a link has been established.