Several explosions have rocked Baghdad, causing at least one fire, and earlier in the day a train was disabled by a makeshift bomb.

An explosion triggered a fire in a row of shops in Baghdad's Old City, where print shops, book, and antique stores are located. Firefighters were able to extinguish the flames.

Also Thursday, a home-made bomb, placed along railroad tracks, crippled a cargo train heading west to the town of Fallujah, about 60-kilometers west of Baghdad. Four of the trains' containers, carrying computers, tents, water and other U.S. military supplies were looted. No one was injured in the incident.

Attacks against military and civilian sites, including Iraqi police stations and the Red Cross headquarters in Baghdad, have caused humanitarian organizations including the Red Cross and the United Nations to decide to remove foreign workers in Iraq, while they assess their future security needs.

The U.S. military says attacks against coalition and Iraqi targets have increased to about 33 a day across Iraq, up from an average of about 15 attacks two-months ago.