Weeks of intense air attacks over northern Iraq have crippled the fighting ability of more than a quarter of Saddam Hussein's army, including Republican Guard elements, Navy commanders say.

Though far from the spotlight of the battle for Baghdad, the carrier-launched airstrikes from the USS Theodore Roosevelt and the USS Harry S. Truman are significant not only for control of the north but also for securing the capital, they say.

In interviews with The Associated Press, commanders and combat pilots attacking northern targets over Turkish airspace described their two-week campaign as less showy than the battle for the capital but crucial in winning the war.

Rear Adm. John C. Harvey Jr., commander of the Roosevelt strike group deployed in the eastern Mediterranean, said the combat sorties from the Roosevelt and the Truman have "significantly degraded the fighting capability" of about 10 Iraqi army divisions.

They have also "severely" hurt the fighting strength of the Iraqi Republican Guard's first, second and fifth corps, he said.

With an Iraqi division numbering 10,000 to 12,000 soldiers, the attacks have crippled about 100,000 troops deployed in a line running from the Turkish border in the north to Iran in the southeast and close to the key Iraqi cities of Mosul and Kirkuk, Harvey said.

Before the conflict, Saddam was thought to command 389,000 full-time, active-duty military, including about 80,000 Republican Guard.

The Pentagon had planned to deploy more than 60,000 troops southward from Turkey to squeeze Baghdad from two sides. But with the Turkish parliament opposed, plans had to be changed.

In the north, Saddam's troops face a mix of U.S. special forces, Kurdish fighters and a 173rd Airborne Regiment that parachuted down March 26 and secured an airfield near the village of Harir.

While control of the airfield has permitted more troops and equipment to be flown in, regular U.S. forces in the north still number no more than around 2,000 soldiers, with little heavy armor.

That prevents them from punching through the Iraqis with heavy armor, which has been successful south of Baghdad, and increases the importance of air power, working together with special operations units that locate targets on the ground and then call down strikes on them.

Once alerted, F/A18 Hornets and F/14 Tomcats from the two carriers release laser or satellite-guided "smart bombs" on targets that have included artillery positions, troop concentrations, surface-to-air missile sites and tanks and other armored vehicles.

Land-based B-52 bombers also are part of the air campaign hitting buildings and other larger targets. But Harvey and senior Navy pilots said much of the damage to the Iraqis came from the 100-plus combat planes flying day and night from the Roosevelt and Truman.

Harvey highlighted an early air strike from the Roosevelt on what Pentagon officials describe as a terrorist camp of the Ansar al-Islam group.

"The destruction the Ansar al-Islam and the al-Qaida terrorists on the Iraq-Iranian border region ... will grow in significance over time" as the camp is thoroughly searched for evidence linking it to terrorist campaigns worldwide, he said.