Josh Brage

BAGHDAD —  Remote-controlled explosives strapped to two mentally retarded women detonated in a coordinated attack on Baghdad pet bazaars Friday, Iraqi officials said, killing at least 73 people in the deadliest day since the U.S. sent 30,000 extra troops to the capital last spring.

The chief Iraqi military spokesman in Baghdad, Brig. Gen. Qassim al-Moussawi, said the female bombers had Down syndrome and that the explosives were detonated by remote control — indicating they may not having been willing attackers in what could be a new method by suspected Sunni insurgents to subvert stepped up security measures.

Secretary of State Condoleezza Rice said the use of mentally retarded women as suicide bombers proves Al Qaeda is “the most brutal and bankrupt of movements” and will strengthen Iraqi resolve to reject terrorism.