The Army's pool of future recruits has dwindled to its lowest level in three years, worrying Pentagon officials as the service is being stretched by the unexpectedly difficult occupation of Iraq.

The Army watches the number of future soldiers in the "delayed entry" program -- those who have enlisted but have not been shipped to boot camp -- as a way to make sure it has enough recruits to keep training camps fully manned in the coming months.

That number has declined to about 23 percent of the number of recruits being shipped this year -- the lowest percentage in three years, said Lt. Col. Bryan Hilferty, a spokesman for the Army's personnel office.

"It is an indicator that troubles us, but it isn't shocking," Hilferty said. He said Army officials believe that the situation is "cyclical" and is likely to recover.

The slippage, Hilferty said, reflects statistical factors more than a new reluctance among American youth -- the Army, he said, has expanded its training base, and so it can take in more recruits rather than making them wait for spaces to become available.

Overall, Hilferty said, Army officials continue to watch the recruiting situation with concern but remain confident that they will meet their targets. The Army's recruiting target for this year was recently raised from 71,500 and is expected to be set at about 77,500, Hilferty said. "There's no doubt that we'll make this year's mission, and we're confident we'll make next year's," he said.

Of his boss, Lt. Gen. Franklin L. Hagenbeck, the head of Army personnel, Hilferty said, "He's concerned about recruiting and retention -- but he's always concerned about recruiting and retention."

Members of Congress also are expressing concern, especially about the National Guard and reserves. Their recruiting has become more difficult in recent months as they have taken on more of the burden of the Iraq occupation. The Guard and reserves make up about 40 percent of the 146,000 U.S. troops there.

"I heard yesterday from the National Guard back home in Missouri that their retention is, as a result of today's situation, sliding downhill very, very fast," Rep. Ike Skelton (D-Mo.) said at a hearing yesterday of the House Armed Services Committee. "Some of the units in the Missouri National Guard are now down to only 80 percent, when they were just a few months ago up to 100 percent."

The Army has relied on several unusual measures in recent months to maintain troop levels in Iraq. It has extended some units there beyond their planned tours of 12 months, it has used "stop-loss" to require some soldiers to stay in the Army after their scheduled end of service, and it has recalled thousands of soldiers who have left active duty and are part of the Individual Ready Reserve.

The Army has called up 5,600 soldiers from the IRR, and about 9,500 of the soldiers on active duty as of Sept. 30 will be part of the stop-loss program -- about 2 percent of the entire Army, said Brig. Gen. Sean J. Byrne, the Army's director of military personnel policy.

Byrne told reporters at the Pentagon last week that he expects the IRR call-ups to continue for deployments to Iraq and Afghanistan in the fall and spring, meaning that thousands of former soldiers -- some of them retirees -- likely will be called back into service in coming months.

Sen. Jack Reed (D-R.I.), a member of the Armed Services Committee, said in an interview yesterday that the Army is clearly stretched too thin in personnel and equipment, with both taking a battering during serious conflicts such as Iraq and Afghanistan. He said using stop-loss and the IRR to fill gaps are dangerous signs.

"There's huge pressure to find any way to make their numbers," said Reed, who has worked to increase the size of the Army and believes the force still needs more. "They're just improvising every day. The fear I have is that there's an immediate cost, but also a much more profound long-term cost."

The latest indication of the strain on the Army is the new disclosure about worries about the size of the delayed entry pool. In 2001, the number of future soldiers in the pool, as a percentage of the number of recruits joining the Army that year, declined to 22 percent, about where the ratio is now, Hilferty said. A year earlier, it had slipped to 19 percent.

Historically, the Army is most comfortable when the level is around 35 percent -- indicating that about one-third of the people who will go to basic training over the next 12 months already have enlisted.

Rep. Ike Skelton said retention in National Guard units in Missouri is "sliding downhill very, very fast."