"As we have surged, we find the enemy surging as well," Maj. Gen. Rick Lynch, commander of the U.S. Army 3rd Division, said. "We're taking the fight to the enemy to counter his capabilities. But over time, especially as we continue to put our forces in areas in which they have never operated, we can expect continued casualties."

The military sustained more than 100 casualties in April, Middle East Newsline reported. The rate has been higher in May as U.S. and Iraqi troops have conducted an offensive against Al Qaida throughout the Baghdad area, Anbar and Diyala provinces.

"Unfortunately, we expect the enemy will break many more hearts in the coming days and weeks," said Lynch, also the commander of Multinational Division Center, which extends from south of Baghdad to the Saudi border.

The commanders said nearly all of the additional U.S. troops would arrive in Iraq in June 2007. They said this would enable an expansion of operations against Al Qaida strongholds identified by U.S. military intelligence.

Commanders said Al Qaida has established recruiting and training centers outside of Baghdad. They said the Islamic insurgency movement has also accumulated weapons and explosives caches north and south of the Iraqi capital in an effort to sustain the daily suicide bomb attacks in Baghdad.

"When these surge units get on the ground, we're going to move to control those sanctuaries, but that's going to come at cost," Lynch told a Pentagon briefing on May 4. "So, everybody has to acknowledge the fact that this is still a very difficult, very dangerous situation that we're working through on a daily basis."