Washington | Boosting U.S. troop levels in Iraq by 21,500 would create major logistical hurdles for the Army and Marine Corps, which are short thousands of vehicles, armor kits and other equipment needed to supply the extra forces, U.S. officials said.

The increase would also further degrade the readiness of U.S.-based ground forces, hampering their ability to respond quickly, fully trained and well equipped in the case of other military contingencies around the world, increasing the risk of U.S. casualties, according to Army and Marine Corps leaders.

"The response would be slower than we might like, we would not have all of the equipment sets that ordinarily would be the case, and there is certainly risk associated with that," the Marine Corps commandant, Gen. James Conway, told the House Armed Services Committee last week.

President Bush's plan to send five additional U.S. combat brigades into Iraq has left the Army and Marines scrambling to ensure the troops could be supported with the necessary armored vehicles, jamming devices, radios and other gear, as well as lodging and other logistics.

Trucks are in particularly short supply. For example, the Army would need 1,500 specially outfitted - known as "up-armored" - 2 1/2-ton and five-ton trucks in Iraq for the incoming units, said Lt. Gen. Stephen Speakes, the Army's deputy chief of staff for force development.

"We don't have the (armor) kits and we don't have the trucks," Speakes said in an interview. He said it will take the Army months, probably until summer, to supply and outfit the additional trucks.

As a result, he said, combat units flowing into Iraq will have to share the trucks assigned to units now there, leading to increased use and maintenance.

Speakes said that although another type of vehicle, the up-armored Humvee, continues to be in short supply Army-wide, there would be "adequate" numbers for incoming forces, and each brigade would receive 400 fully outfitted Humvees. But he said that to meet the need, the Army would have to draw down pre-positioned stocks that would then not be available for other contingencies.

Shortage 'inevitable'?

Still, U.S. commanders privately expressed doubts that Iraq-bound units would receive a full complement of Humvees. "It's inevitable that that has to happen, unless five brigades of up-armored Humvees fall out of the sky," one senior Army official said of the feared shortfall.

He anticipated that some units would have to rely more heavily on Bradley Fighting Vehicles and tanks that, although highly protective, are intimidating and therefore less effective for many counterinsurgency missions.

Adding to the crunch, the U.S. government has agreed to sell 600 up-armored Humvees to Iraq this year for its security forces. Such sales "better not be at the expense of the American soldier or Marine," Speakes told defense reporters recently, saying that U.S. military needs must take priority.

Living facilities in Iraq are another concern for the additional troops, who would be concentrated in Baghdad, Army officials said. The U.S. military has closed or handed over to Iraqi forces about half of the 110 bases established there after the U.S.-led invasion in 2003.

Decisions are being made on where to base incoming units in Baghdad, but it is likely that, at least in the short term, they would be placed in existing facilities, officials said.

Lt. Gen. David Petraeus, the new top U.S. commander in Iraq, has requested that additional combat brigades move into Iraq as quickly as possible. But accelerated deployments would mean less time for units to train and fill out their ranks.

Brigades are required to have an aggregate number of soldiers before deploying but may still face shortages of specific ranks and job skills.

Meanwhile, the demand for thousands more U.S. forces in both Iraq and Afghanistan is worsening the readiness of units in the United States, depleting their equipment and time to train, Army officials said.

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