Washington ? Under pressure to meet combat needs, the Army and Marine Corps brought in significantly more recruits with felony convictions last year than in 2006, including some with manslaughter and sex crime convictions.

Data released by a congressional committee shows the number of soldiers admitted to the Army with felony records jumped from 249 in 2006 to 511 in 2007. And the number of Marines with felonies rose from 208 to 350.

Those numbers represent a fraction of the more than 180,000 recruits brought in by the active duty Army, Navy, Air Force and Marines during the fiscal year ending Sept. 30, 2007. But they highlight a trend that has raised concerns both within the military and on Capitol Hill.

The bulk of the crimes involved were burglaries, other thefts, and drug offenses, but nine involved sex crimes and six involved manslaughter or vehicular homicide convictions. Several dozen Army and Marine recruits had aggravated assault or robbery convictions, including incidents involving weapons.

Both the Army and Marine Corps have been struggling to increase their numbers as part of a broader effort to meet the combat needs of a military fighting wars on two fronts. As a result, the number of recruits needing waivers for crimes or other bad conduct has grown in recent years, as well as those needing medical or aptitude waivers.

House Oversight and Government Reform Committee Chairman Henry Waxman, who released the data, noted that there may be valid reasons for granting the waivers and giving individuals a second chance.

But he added, “Concerns have been raised that the significant increase in the recruitment of persons with criminal records is a result of the strain put on the military by the Iraq war and may be undermining military readiness.”

The services use a waiver process to let in recruits with felony convictions, and many of the crimes were committed when the service members were juveniles.

For example, in several of the Marine sex crime cases, the offender was a teenager involved in consensual sex with another underage teen. In one Army case, a 13-year-old who threw a match into his school locker was charged with arson and had to receive a felony waiver six years later.

“Waivers are used judiciously and granted only after a thorough review,” said Pentagon spokesman Lt. Col. Jonathan Withington.

He added that “low unemployment, a protracted war on terror, a decline in propensity to serve,” and the growing reluctance of parents and teachers to recommend young people go into the military, has made recruiting a challenge.

According to the Army, 18 percent of the recruits needed conduct waivers in the fiscal year ending Sept. 30, 2007, compared with 15 percent in the 12-month period ending Sept. 30, 2006. “We are growing the Army fast and there are some waivers; we know that,” said Army Lt. Gen. James D. Thurman, deputy chief of staff for operations. “It hasn’t alarmed us yet.”

He said that “the better part of making soldiers is about leadership. Somebody invested in me, you know. That’s the beauty of the United States Army. It’s about leadership. … You’ve got to give people an opportunity to serve.”