WASHINGTON — The United States will fall well short of meeting its goal of training 24,000 Iraqi forces to fight Islamic State militants by this fall, Defense Secretary Ashton Carter said Wednesday on Capitol Hill, where lawmakers were already skeptical of the Obama administration’s strategy to address threats in the Mideast.
Carter told the House Armed Services Committee that the United States has received only enough recruits to train about 7,000 — in addition to about 2,000 counterterrorism service personnel.
‘‘Our training efforts in Iraq have thus far been slowed by a lack of trainees. We simply haven’t received enough recruits,’’ Carter said at a nearly three-hour hearing.
The defense secretary said the train-and-equip mission in Syria also lacks enough trainees to fill existing training sites, primarily because it’s difficult to make sure the recruits are people who can be trusted and are not aligned with militant groups.
‘‘It turns out to be very hard to identify people who meet both of those criteria,’’ Carter said.
Later in the day, the House rejected a resolution to force Congress to debate an Authorization for the Use of Military Force for US military engagement in Iraq and Syria.
There are no US troops in Syria and about 3,500 in Iraq are assisting the nation’s security forces.
The Iraqi military, which was equipped and trained by the United States, has struggled to recover from its collapse a year ago when Islamic State militants captured the country’s second-largest city, Mosul, and swept over much of northern and western Iraq. Iraqi commanders fled, pleas for more ammunition went unanswered, and in some cases soldiers stripped off their uniforms and ran.
The United States is again training Iraqi forces and conducting airstrikes in both Iraq and Syria.
The White House said last week it was sending up to 450 more US troops to a new base in the Anbar province of western Iraq, mainly to advise the Iraqis on planning and executing a counteroffensive to retake Ramadi, the provincial capital.
More US hubs could be opened elsewhere in Iraq as the campaign advances.
Staunch critics in Congress have argued that the current strategy is weak and that it could be strengthened by deploying US troops as spotters for airstrikes.
The Pentagon thus far has avoided putting tactical air controllers in the field with Iraqi ground forces and remains opposed to having US troops more actively involved in the ground war.
‘‘I would not recommend that we put US forces in harm’s way simply to stiffen the spine of local forces,’’ General Martin Dempsey told the committee. ‘‘If their spine is not stiffened by the threat of ISIL on their way of life, nothing we do is going to stiffen their spine,’’ he said, using an acronym for the Islamic State.
Dempsey, who is finishing a four-year stint as chairman of the Joint Chiefs of Staff, said that when the local forces are going against a strategic target, the Pentagon might see how US personnel could help ensure the local forces’ chances of success — ‘‘but not just to stiffen their spine.’’
Asked whether the 450 extra troops will make a difference in the fight, Carter said the numbers are not as significant as the location, which is in the heart of Sunni territory. The United States is pushing for a more inclusive government in Baghdad that is representative of Sunnis, Shi’ites, and Kurds, Iraq’s three major ethnic groups.
At the White House, press secretary Josh Earnest defended the White House strategy in Iraq, saying 1,000 new Sunni fighters were inducted into the Iraqi popular mobilization force last week. ‘‘I understand that even just today, another ceremony was held where several hundred additional Sunni local fighters were inducted,’’ he said.
After the hearing, Republican Representative Mac Thornberry of Texas, the panel’s chairman, that he’s not sure that Carter or Dempsey convinced the committee that the US strategy would be successful.
‘‘So we’re opening a new facility in a different part of Iraq to train and we hope they come flooding in and they will be trained and effective and then we’ll see if we can support them. It just doesn’t give you a lot of confidence that this thing is on the right track,’’ Thornberry said.
Representative Adam Smith, the committee’s ranking Democrat, questioned whether it’s not time to admit that Iraq is too fractured to continue trying to work through the central government in combating Islamic State militants.
He asked whether Baghdad should be told, ‘‘time’s up,’’ and the United States cannot afford to continue hoping a government of national unity can be established. ‘‘As I’ve said many times before, that cow has left the barn. Iraq is fractured. You can make a pretty powerful argument, in fact, that Iraq is no more,’’ Smith said.
Representative James Langevin, a Rhode Island Democrat, also wondered about divisions among the Kurds, Shi’ites, and Sunnis. ‘‘Are we trying to artificially hold together an Iraq that doesn’t want to be held together?’’ he asked.