At least 48 people died and at least 286 others were wounded in 13 cities. The locations included Baghdad, the capital, and large towns in the northern, western, and southern quadrants of the nation. The only region that appeared to be spared the onslaught was the three-province Kurdish autonomous region in the north.

Investigators don't yet know whether these strikes were coordinated, but a similar series of strikes that occurred in May bore the hallmarks of al Qaeda in Iraq. On that day, 85 people died and more than 300 others were wounded in coordinated shootings and bombings across six provinces.

The latest attacks come as the number of U.S. troops in Iraq has now fallen below 50,000 -- the lowest level since the U.S-led invasion in 2003. The U.S.-led combat mission formally ends August 31, and the remainder of American troops will train, assist and advise the Iraqis.