Saddam's chemical belt: report
"There was a report from the resistance groups inside Iraq that Saddam has considered setting up a chemical belt around Baghdad, entrapping about 4 million residents in the city and using them as a human shield," Hussein Al-Shahristani told the network.
"That is what I heard from some political activists inside the country recently."
CNN described Shahristani as a former nuclear researcher who left Iraq after spending 12 years in prison, from 1979 to 1991.
The chemical weapons would be shallowly buried, spaced about 100m apart, and linked to detonators at Saddam's command centre, he said.
"Whenever he decides the time is right, he will try to detonate it so as to entrap the people inside the city and also to hinder the advancement of the troops to the city," he said.
Sharistani said he was "sure" Saddam would want to build the chemical weapons belt but that many of his soldiers might turn against him before it is done, the network reported.
He said UN weapons inspectors had not been able to detect the regime's neurotoxic agents because they are hidden in secret tunnels.