Marines in Fallujah point out blast marks on their Mine Resistant Ambush Protected Vehicles to members of the media during a visit by Defense Secretary Robert Gates to Camp Fallujah on April 19 in Iraq's Anbar province. To date, no U.S. troops have been killed while riding in the heavily-armored MRAPs in the Iraq war.

Camp Fallujah, Iraq ? The armored carrier has a grim black slash across its side, burn marks on the door and a web of cracks along the window.

Like most of the Mine Resistant, Ambush Protected, or MRAP, vehicles in Anbar province, this one has been hit as many as three times by enemy fire and bomb blasts. Yet, to date, no American troops have died while riding in one.

But efforts to buy thousands more carriers – each costing about $1 million – could be delayed if the White House and Congress do not resolve their deadlock over a $124.2 billion war spending bill.

About $3 billion for the vehicles is tied up in the legislation. The spending plan has stalled because of a dispute over provisions that would set a timetable for the withdrawal of U.S. troops from Iraq.

At a hearing last month, lawmakers urged the Army to get more of the carriers to the battlefront as quickly as possible. The vehicles, with their unique V-shaped hull that deflects blasts outward and away from passengers, are considered lifesavers against the No. 1 killer in Iraq – roadside bombs.

Military leaders say the carriers have reduced roadside bomb casualties in Iraq by as much as two-thirds. But they are not effective against the enemy’s latest weapon – explosively formed penetrators, which hurl a fist-sized lump of molten copper capable of piercing armored vehicles.

Right now, there are at least 1,100 of the armored carriers on the battlefront in Iraq, including the 100 or so that rumble through Anbar province carrying troops and clearing roads of explosives.

The Army, Marines, Navy, Air Force and Special Operations forces want thousands more. The goal is more than 7,700, at a cost of about $8.4 billion.

The Army wants 2,500, at a cost of about $2.7 billion. The Marines are planning to buy 3,700 and would send about 3,000 to Iraq.

There will be 525 in the country by the end of the year, said Brig. Gen. Mark Gurganus, ground combat commander for U.S. forces in western Iraq.

As the Pentagon scrapes to find the money to run the war in the midst of the budget impasse, the Pentagon says there is not enough cash to buy as many as commanders say they need.

“We can build what we can get the funds to build. It’s strictly an issue of money,” Gen. Peter Schoomaker, former Army chief of staff, told a Senate committee last month.

At the time, he said the Army had an unfunded requirement of about $2 billion. Lawmakers added some additional money to the bill, so that number would now be about $1.5 billion.

He said the Army believes “that not only do we need the MRAP immediately to give us better protection, but that we need to stay on a path to get an even better vehicle than the MRAP for the long haul, because the enemy is going to continue to adapt.”

Senators pressed for more. “We’re buying far too few of them,” said Sen. Byron Dorgan, D-N.D. “If we have that capability, why would we not do everything to mobilize, to move as many of them into the field as is possible?”