BAGHDAD — The Iraqi Interior Ministry ordered police yesterday to begin rounding up beggars, homeless and mentally disabled people from the streets of Baghdad and other cities to prevent insurgents from using them as suicide bombers.

The decision, which elicited concern from advocates for the mentally disabled, came nearly three weeks after twin suicide bombings against pet markets. Officials said those blasts were carried out by mentally disabled women who may have been unwitting attackers. The American military and the Iraqi government have claimed that Sunni insurgents led by Al Qaeda in Iraq are increasingly trying to use Iraq’s most vulnerable populations as suicide bombers to avoid raising suspicions or being searched at checkpoints that guard access to many markets, neighborhoods, and bridges in the capital.

The people detained in the Baghdad sweep will be handed over to social welfare institutions and psychiatric hospitals that can provide shelter for them, an Interior Ministry spokesman, Major General Abdul-Karim Khalaf, said.

“This will be implemented nationwide starting today,” General Khalaf told the Associated Press in a telephone interview.

“Militant groups, like Al Qaeda in Iraq, have started exploiting these people in the worst way to kill innocent victims because they do not raise suspicions,” General Khalaf said. “These groups are either luring those who are desperate for money to help them in their attacks or making use of their poor mental condition to use them as suicide bombers.”

It isn’t clear such people would be safe in psychiatric hospitals. American and Iraqi troops recently detained the acting director of al-Rashad psychiatric hospital in eastern Baghdad on suspicion of helping supply patient information to Al Qaeda in Iraq.