President Bush called off a planned covert raid into northern Iraq late last week that was aimed at a small group of al Qaeda operatives who U.S. intelligence officials believed were experimenting with poison gas and deadly toxins, according to administration officials.
The experiments were being run under orders from a senior al Qaeda official who was providing money and guidance from elsewhere in the region.
U.S. officials familiar with the joint CIA and Pentagon operation said they were concerned they might be dealing with what could have been a budding chemical weapons laboratory.
Intelligence sources said the al Qaeda operatives were under the protection of a small radical Kurdish group called Ansar al Islam. It is a radical Islamic faction closely allied with al Qaeda that operates in a part of northern Iraq controlled by Kurds.
Since the Persian Gulf War, the United States has operated a so-called no-fly zone over much of northern Iraq to protect the Kurds from Saddam Hussein's periodic crackdowns. U.S. officials say they have no evidence Saddam's government had any knowledge of the al Qaeda operation.
Deadly Substance From the Castor Bean
Most of the experiments, sources say, involved a poison called ricin, a byproduct of the widely available castor bean plant.
"It is quite toxic, probably seven times more toxic than phosgene, which was a chemical weapon used in World War I," said Jonathan Tucker, director of the Chemical and Biological Weapons Nonproliferation Program at the Monterrey Institute of International Studies.
Once a person is exposed to sufficient quantities, by inhalation or ingestion, ricin is deadly. "There is currently no treatment and no vaccine for ricin exposure," Tucker explained.
It is especially appealing to a terrorist group because it is relatively easy to make, easy to handle and is not expensive.
As a potential weapon of terror, ricin is considered most deadly in a closed room or building, where nearly everyone could die.
In World War I, the British experimented by putting ricin in artillery shells and bombs, but they never used it on the battlefield.
Tested on a Man
Intelligence sources told ABCNEWS there is evidence the terrorists tested ricin in water, as a powder and as an aerosol. They used it to kill donkeys, chickens and at one point allegedly exposed a man in an Iraqi market.
They then followed him home and watched him die several days later, sources said.
As U.S. surveillance intensified, officials concluded the operation was not a major threat to the United States and definitely not a sophisticated laboratory.
Instead, it appeared to be a few terrorists with relatively small amounts of poisons who were being encouraged to experiment by al Qaeda managers elsewhere in the region.
In the final analysis, the White House, Pentagon and CIA concluded it was not worth risking American lives to go after these people and not worth the adverse publicity that would surely follow any U.S. operation inside Iraq.
But as part of this operation, intelligence analysts did discover that al Qaeda money was again flowing, that new people had stepped in to manage and encourage far-flung projects like this one — offering glimpses of a terrorist network trying to put itself back together again.