FORT BRAGG - Nine soldiers killed in a double suicide truck bombing on their outpost belonged to a small Fort Bragg unit that has taken a staggering number of casualties in recent weeks.

The 5th Squadron, 73rd Cavalry of the famed 82nd Airborne Division went to Iraq with about 330 soldiers, but has lost 18 in just five weeks, as well as two others late last year. The squadron's casualty rate has climbed so high so quickly that it has turned families' nagging worries into vivid fear.

Kara Honbarger, 29, figures that if anything happens overnight to her husband, squadron chaplain Capt. Craig Honbarger, that the notification team will show up about 6:30 a.m.

"I think most of us look out our windows in the morning to make sure there's no car there," she told reporters Tuesday afternoon at Fort Bragg. "I think we get nervous when the doorbell rings."

The squadron is fighting in an insurgent stronghold, Diyala province, that for much of the war has been overshadowed by fighting in Baghdad and Anbar province, but is emerging as one of the most dangerous places for U.S. troops.

The attackers struck the small outpost in the tiny town of Sadah in the afternoon, said Lt. Col. Michael Donnelly, a U.S. military spokesman in north Iraq, via e-mail.

The attackers used two dump trucks filled with explosives, according to The Associated Press.

Amid a heavy defensive fire from the paratroopers, the first of the giant rolling bombs slammed into a ring of concrete barriers protecting the post and exploded, opening a pathway. The second rammed the wreckage, dragging it before exploding 30 yards from the building housing the post's troops, collapsing two walls.

Twenty soldiers were injured, and five, along with an Iraqi translator were hurt badly enough to be evacuated for treatment.

According to AP, an al-Qaeda-linked group posted a Web statement Tuesday claiming responsibility for the bombing.

The attack was the worst against U.S. forces in Iraq since Dec. 1, 2005, when a roadside bomb killed 10 Marines near Fallujah.

Division's losses rise

Monday's deaths have pushed the 82nd to some grim mileposts.

The division has now lost 28 paratroopers in seven weeks in Iraq, a number that exceeds the division's toll for any previous full year in the war. Monday's attack itself killed more of the division's paratroopers than any since the Vietnam War. An ambush in 1969 left 12 dead, although records are sketchy, said John W. Aarsen, curator of the division's museum.

One reason for the squadron's casualties is that Diyala had become a haven for Sunni insurgents and other fighters squeezed out of Baghdad by the troop buildup. U.S. military leaders sent 700 more soldiers there last month.

The area in which the 5th Squadron has been operating includes some of the most perilous turf, such as a string of impoverished small towns along the Diyala River known for large numbers of insurgents and criminals.

Four paratroopers from the squadron were killed in a bomb blast April 7 in the village of Zaganiya on the Diyala River about 30 miles north of Baghdad. That came just days after members of the unit had joined other U.S. troops and Iraqi soldiers in uncovering a large weapons cache and an insurgent training camp near the village. Much of the land around the river is heavily vegetated, which makes good cover for attackers.

The squadron lost four other soldiers in a bomb blast in the nearby city of Baqubah on March 25. Another paratrooper was killed in a bomb blast March 17, that one also in Baqubah.

The attack Monday also underlined one of the perils of Gen. David Petraeus' commitment to classic counterinsurgency techniques. Commanders are pushing troops out of massive bases and putting them in hundreds of small outposts where they can be a constant presence and boost security. The change makes troops more vulnerable.

'Bad guys simply wait'

Kenneth Pollack, a counterinsurgency expert at the Brookings Institution, a Washington think tank, said that keeping the troops on big bases was one of the biggest mistakes of the first four years of the war.

"There is no other way to do this," Pollack said. "Keeping the troops on the [big bases] means that they are somewhat better protected but are also pretty much useless. They do not serve as any kind of deterrent to the security problems, nor are they ever present when someone needs help. The bad guys can simply wait till the occasional patrol passes by and then go about their business."

That's no comfort to the 5th Squadron's home front.

Maj. Jim Brisson, deputy division chaplain, said he had notified some of the families of the nine soldiers killed.

"It is a pain that is unbearable, as you're approaching doors to tell family members this. It is often times with fear and trepidation, yet it is often with a honor and a sense of great humbleness that you go forward."

Kara Honbarger -- who with her husband has children ages 5, 3 and 5 months -- said recent attacks and casualties changed the families' outlooks.

"I'm more worried not only for my own husband but the rest of our husbands," she said. "They are in a very hostile area and it's scary. The first half of the deployment they hardly ran into anything. Now they're running into everything."