A string of heavy losses from powerful roadside bombs has raised new questions about the vulnera- bility of the Stryker, the U.S. Army's troop-carrying vehic- le hailed by supporters as the key to a leaner, more mobile force.
Since the Strykers went into action in Diyala province north of Baghdad two months ago, losses of the vehicles have been rising, U.S. officials say.
A single infantry company in Diyala lost five Strykers last month in less than a week, said soldiers familiar with the losses who spoke on the condition of anonymity because they are not authorized to issue such information. The overall number of Strykers lost recently is classified.
In one of the bloodiest incidents, six American soldiers and a journalist were killed when a bomb exploded beneath their Stryker on May 6. It was the largest one-day loss for the battalion in more than two years.
"We went for several months with no losses and were very proud of that," a senior Army official said in Washington, speaking on the condition of anonymity because he is not authorized to comment publicly. "Since then, there have been quite a few Stryker losses."
"They are learning how to defeat them," the official said of Iraqi insurgents.
The Army introduced the $11 billion, eight-wheel Stryker in 1999 as the cornerstone of a ground force of the future, hoping to create faster, more agile armored units than those relying on tanks, but with more firepower and protection than light-infantry vehicles.
But the Army and the Marines are looking for something different that can survive big roadside bombs -- the main threat to soldiers in Iraq -- meaning the Stryker's high-profile status as the Army's "next generation" vehicle may be short-lived.
"It is indeed an open question if the Stryker is right for this type of warfare," said Michael O'Hanlon, a senior analyst with the Brookings Institution. "I am inclined to think that the concept works better for peacekeeping. But based on data the Army has made available to date, it's hard to be sure."
Supporters of the Strykers, which have been used in Iraq since late 2003, say the vehicles that carry two crew members and 11 infantrymen offer mobility, firepower and comfort.
Lighter and faster than tracked vehicles like tanks, each Stryker can rush soldiers quickly to a fight, enabling commanders to maintain security over a wide area with relatively fewer troops. Humvees can carry only four soldiers and are more vulnerable to bombs even when their armor is upgraded.
"I love Strykers," said Spc. Christopher Hagen, based in Baqouba. "With Strykers, you're mobile, you're fast. You can get anywhere any time. They bring a lot of troops to the fight."
But some analysts have long questioned the wisdom of moving away from more heavily armored tracked vehicles like tanks and Bradley fighting vehicles to wheeled transports, such as the Stryker.
They say that is especially true in Iraq, where powerful bombs -- not rocket-propelled grenades or small-arms fire -- are the main threat.
"The Stryker vehicle was conceived at a time when the Army was more concerned about mobility and agility than it was about protection," said Loren Thompson, a military analyst from the Lexington Institute. "Stryker was the answer to that need."
The Stryker's vulnerabilities have become increasingly apparent since a battalion of about 700 soldiers and nearly 100 Stryker vehicles from the Army's 2nd Infantry Division was sent to Diyala province in March to bolster an infantry brigade struggling to restore order there.
Trouble started as soon as the Strykers arrived in Baqouba, Diyala's provincial capital.
U.S. commanders ordered the vehicles into Baqouba's streets at dawn the day after they arrived. The hope was that the large, menacing vehicles -- armed with a heavy machine gun and a 105mm cannon -- would intimidate insurgents and reassure local residents.
Instead, insurgents hammered the Strykers with automatic weapons fire, rocket-propelled grenades and a network of roadside bombs. By the end of that first day, one American soldier was dead, 12 were wounded and two Strykers were destroyed.
Since then, the losses have mounted. A few days before the attack that killed the six soldiers and a Russian journalist, troops scrambled out of another damaged Stryker and took cover in a house while they watched their vehicle burn. Several of them were injured but none seriously.
Lt. Col. Bruce Antonio, who commands a Stryker battalion in Diyala, said he and the soldiers still have confidence in the Strykers and noted they have survived many bombs, which the military calls improvised explosive devices or IEDs.
But Col. Antonio said some insurgents had found "the right mix of explosives and IED positioning to inflict severe damage on the vehicle." He noted that tanks also have proved vulnerable.
The insurgents apparently are becoming better at hiding the devices -- the IED that killed the six soldiers and the journalist was thought to have been hidden in a sewer line. To add potency, insurgents surrounded the device with cement to channel the blast force up into the tank, said soldiers familiar with the investigation.
Supporters of the Strykers say all this proves that it's the lethality of bombs in Iraq -- not the Strykers -- that are the problem: The bombs are now so powerful that even Abrams main battle tanks are vulnerable to some of them.
"I'm not sure if it's any reflection on the [Stryker] but rather on how things are getting worse" in Iraq, said a senior Democratic congressional staffer who tracks Army programs. He spoke on the condition of anonymity because he wasn't authorized to speak publicly.
Stryker soldiers said that when they were based in Mosul, in the north, roadside bombs weren't so big -- often, little more than pipe bombs. In Baqouba, the bombs are bigger and buried deeper, making them hard to detect.
"With what we got hit with the other day, it wouldn't have mattered what we were in," said Spc. John Pearce, speaking of the May 6 bomb. "We were going to take casualties, regardless."
Either way, the Army and Marine Corps are pushing for new Mine Resistant Ambush Protected vehicles, or MRAPS, whose V-shaped hulls are designed to deflect bomb blasts outward, rather than through the vehicle.
The Pentagon is seeking nearly 7,800 of the new vehicles at a cost of $8.4 billion and is considering ordering thousands more to give soldiers better protection.
Such moves, however, only reinforce the views of critics, who think the Army opted for a vehicle that was useful in Balkan peacekeeping or other "low threat" missions but is inadequate in "asymmetric warfare," where a weaker opponent devises simple tools to exploit a strong opponent's weak points.
"As long as the Stryker-equipped light infantry was used ... against lightly armed insurgents, there was no problem," said retired Col. Douglas Macgregor, who writes on defense issues.
"Now, they are being tossed into the urban battle, where only tracked armor can survive."
c Robert H. Reid reported from Baghdad and Anne Flaherty from Washington. AP reporters Todd Pitman in Diyala, Iraq, and Pauline Jelinek in Washington also contributed to this report.