The U.S. military says the tactics used by al-Qaida in Iraq, including the use of women and mentally impaired suicide bombers shows how desperate the terrorist network is. Daniel Schearf reports from the northern Iraqi city of Irbil.

The U.S. military says al-Qaida in Iraq is changing tactics in response to stepped-up security measures that have curbed violence in the country.

Insurgent attacks have dropped by 60 percent since June after an additional 30,000 U.S. troops arrived in Iraq and Sunni and Shia militias declared cease-fires or offered to cooperate.

Iraqi officials say improvements in security have reduced attacks in Baghdad by 80 percent.

However, attacks believed to be carried out by al-Qaida inspired insurgents have continued and officials say increasingly involve female suicide bombers to try to get past male security who are reluctant to search women.

More disturbing was the recent use of mentally impaired women who were likely not completely aware of what they are doing.

Major Alan Stout is a spokesman for the U.S. military in Baghdad. He tells VOA these tactics indicate desperation. "We've seen these female suicide attackers coming from different areas outside of Iraq even from Syria, Yemen? So, they're really just scraping the barrel wherever they can find? they're using women who are mentally handicapped, we've even seen handicapped children being involved," he said.

At least five women have carried out suicide bombings in Iraq since November.

On Sunday a female suicide bomber detonated in Baghdad after being stopped by Iraqi security.

Iraqi police said several people were killed or wounded in the attack. The U.S. military says only the suicide bomber died.

Earlier this month, two mentally impaired women strapped with explosives were remotely detonated in Baghdad pet markets, killing almost one hundred people.

Security forces later arrested the director of Baghdad's largest psychiatric hospital on suspicion he was supplying information about patients to the terrorists. He is still being investigated.

Also Tuesday, the trial of two former Iraqi health officials accused of supporting Shi'ite death squads was postponed after key witnesses failed to appear in court after receiving threats.

The former Deputy Health Minister, Hakim al-Zamili, and former head of ministry security Brig. Gen. Hameed al-Shimmari, are accused of helping militiamen from the Mahdi army use ambulances and hospitals to kidnap and kill Sunni Muslims.