Recruiters say that some 60,000 to 70,000 men have joined up since the June 13 religious edict—considerably less than the numbers thrown around by some politicians. The Iraqi government does not disclose troop levels. Retired U.S. Lt. Gen. James Dubik, who once led the training of Iraq’s military, estimated the overall size of Iraq’s forces at about 700,000.

Iraq’s military appeared ill-prepared to integrate the new recruits. Some soldiers were asked to buy their own uniforms in public shops in downtown Baghdad. Unable to provide food, the army took donations from wealthy benefactors, mostly Shiites.

“It was like a mowakib,” said Khaled Johi, a recruitment officer, referring to the Shiite practice of distributing meals to the poor during Shiite religious holidays…

Sunni politicians like Mr. Mutlaq are worried that the accelerated enlistment of Shiites could lead to abuses as religious passion meets lax military discipline. Iraqi military officials acknowledge the risk but say they have no other choice for filling the ranks.