These explosives are no bigger than a man's fist are easy to build and can be tucked quickly under the bumper of a car and detonated remotely, Te New York Times reported Friday.

As security in Baghdad improves, the small bomb is being used more often but the devices are usually less lethal than weapons carried by suicide bomber, the Times says.

"The safety barriers, the walls themselves, have largely taken away these catastrophic attacks that you saw in the past," U.S. Army Lt. Col. Steven Stover, a U.S. military spokesman in Baghdad, told the Times. "The smaller bombs are not capable of causing that catastrophic attack but they're causing a lot of panic."

Sticky bombs have become more common since the start of this year, from an average of two explosions a week caused by them this spring, to about five per week more recently, Stover said.