"The Iraqi ministry of health asked us to go to Falluja. When we were on our way, the US army stopped our convoy, and carried out a search," said Dr Ibrahim al-Kubaisi.

"After we waited in the US base, located near Falluja, for four hours, a doctor told us that they had agreed with the Iraqi ministry of health to send a medical team to Falluja but only after eight or nine days.

"There is a terrible crime going in Falluja and they do not want anybody to know. I transferred four injured people from the Jordanian field hospital to a hospital in Baghdad.

"They told me that there is a crime in there; chemical weapons are being used. The corpses don't have traces of gunshots but black patches.

"US forces allow people to go into al-Hadra al-Muhammadiya area, in Falluja, but they prohibited anybody to enter al-Julan, al-Askari and al-Senai neighbourhoods.

"There are Iraqi families under siege in there," the doctor said.

The humanitarian situation for Falluja residents has been reported to be dire. Thousands of Falluja residents have fled the city and are living in makeshift shelters surrounding the city.