In pictures: Day of carnage

1 of 6 US and Iraqi military and police vehicles raced to the scene of an explosion in Baghdad.

2 of 6 A suicide bomber had detonated his explosives belt after mingling with men queuing to join the Iraqi army.

3 of 6 Dozens were injured in the blast.

4 of 6 Many others were clearly beyond help.

5 of 6 Police made several arrests at the scene.

6 of 6 Suicide bombers also struck in the northern cities of Mosul and Kirkuk, where a suicide car bomber blew up a Mercedes near municipal buildings.