Washington: Iraq could unleash a biological attack on the West by using unsuspecting people travelling abroad as carriers of deadly germs, a prominent Iraqi defector warned on September 19.

Nuclear scientist Khidhir Hamza, who left Iraq in 1994 and now lives in the United States, told the US Congress he suspected the Iraqi security service, which runs the country's biological weapons programme, had already used people travelling abroad to reunite with relatives to infect exiled dissidents with the deadly AIDS virus.

"An angle rarely reported, and I found extensive incidents regarding it when I left Iraq and worked in Libya from Iraqi expatriates, was the use of humans as disease carriers," Hamza told the House Armed Services Committee.

He said he knew of Iraqi dissidents living abroad, who suddenly got word from Baghdad that their families had been allowed to leave Iraq and reunite with them.

Under Iraqi public health procedures, people going abroad must be vaccinated against several standard infectious diseases before they can obtain passports.

Hamza said some of these inoculations might have been used by the security service, Mukhabarat, to infect people with viruses like HIV in the hope that they would be passed on to targetted dissidents.

"There were many incidents of whole families infected this way with HIV and other diseases," he said.

Iraqi people with AIDS are sent to a remote facility in the Western desert called Salman Hole, presumably for treatment, the scientist said.

However, he said, nobody had ever come back from the camp and he suspected the patients were being used by Mukhabarat for biological experiments and virus collection.

"If smallpox is to be sent abroad from Iraq, one should expect unwitting carriers being sent to the destination targets, possibly not even Iraqis, to achieve deniability," Hamza said.