WASHINGTON – Military officials said Thursday they were working hard to upgrade the armor on Army vehicles in Iraq, a day after a soldier had pressed Defense Secretary Donald H. Rumsfeld on the subject. President Bush said, “The concerns expressed are being addressed.”

Close to three-quarters of the Humvees in the Iraq war theater now have upgraded armor protection, but many larger trucks and tractor-trailer rigs do not, according to congressional figures.

Military officials said that armoring Humvees has been the top priority because they are used to patrol areas where attacks are likely. The heavy haulers, meanwhile, usually travel convoy routes that are more frequently swept for guerrillas and bombs.

The issue of whether the military is providing enough protection to soldiers is receiving new attention after a National Guardsman on his way to Iraq questioned Rumsfeld on Wednesday as to why he and his comrades had to scrounge through scrap piles to protect their vehicles.

Lt. Gen. Steven R. Whitcomb, commander of the 3rd Army, was questioned about that by Pentagon reporters Thursday in a teleconference from Camp Arifjan, Kuwait.

“If I can add another plate or another inch or more to the vehicle I’m riding in that gives me protection, it’s better,” he said. “So I think that’s a prudent thing to do, if the soldier has the capability. … In my opinion, it’s not being done in mass numbers or mass quantities.”

He said vehicles with upgraded armor were being added every day. “Our goal, and what we’re working toward, is that no wheeled vehicle that leaves Kuwait going into Iraq is driven by a soldier that does not have some level of armor protection on it,” he said.

At the White House in Washington, Bush, too, was asked about the situation.

“The concerns expressed are being addressed and that is – we expect our troops to have the best possible equipment,” Bush said. “If I were a soldier overseas wanting to defend my country, I’d want to ask the secretary of defense the same question. And that is, ‘Are we getting the best we can get us?’ And they deserve the best.”

Questions have been raised about why the military had not started armoring its vehicles sooner than August 2003, when insurgents turned to bombs to attack U.S. forces. Some critics point to the lack of light armored vehicles as further evidence the Bush administration was unprepared for the kind of insurgency it has faced in Iraq.

It’s the big trucks that do much of the heavy hauling around Iraq, ferrying supplies, troops and even other vehicles through rough stretches of highway. The better-known Humvee serves as a light troop carrier, weapons platform and all-purpose jeep.

But the big trucks, like the 5-ton M939 medium truck and the tank-hauling Heavy Equipment Transporter, face some of the same threats as the Humvees, including roadside bombs and gun and rocket ambushes.

Some have weapons on board, but very few have armor, and of those that do, the armor offers less protection than is carried by many Humvees.

As to the issue of soldiers turning to scrap piles to better protect their vehicles, senior military officials have offered a few explanations. One is that units heading into Iraq are allowed to scavenge outgoing and damaged vehicles for spare armor plates.

In addition, officials acknowledge, soldiers will sometimes come up with ways to better protect themselves, and perform extra modifications to their vehicles. This may be a spare armor plate or sandbags on the floor, or some other fix.

Of more than 9,100 heavy military haulers in Iraq, Afghanistan and nearby countries, just over 1,100 have received upgraded protection, according to figures provided by the House Armed Services Committee in Washington. Armor add-on kits are in production for many of the rest of these vehicles.

By comparison, the military has decided it needs almost 22,000 armored Humvees in the war area. It has 15,334; an additional 4,400 await armor add-ons and the rest have not been delivered to the region.

Those Humvees are being built at the rate of 450 a month. The company armoring them, Armor Holdings Inc., said Thursday it could increase production by 50 to 100 vehicles a month.

Humvees are armored in two ways: at the factory or in the field. The factory-armored vehicles are considered the best-protected, and the military says it needs 8,105 in Iraq, Afghanistan and nearby countries. It has 5,910. About 120 have been destroyed, Whitcomb said. The rest are protected with add-on kits of armor that can be bolted to a regular unarmored Humvee.

Manufacturers are making these kits at a rate of 800 a month. Some 4,300 Humvees remain unarmored.