D.C. Council members, advocates and parents raised questions Monday about Mayor Vincent C. Gray’s push to reduce the number of special-education students who attend private schools at public expense.

The effort has saved tens of millions of dollars and reduced segregation of students with disabilities, but it has triggered concerns that some students are being made to attend city schools that aren’t equipped to handle their needs.

“We all want to believe that [D.C. Public Schools] is getting stronger and has the capability to do this, but it’s time for us to peek behind the curtain a little bit,” said Council member David A. Catania (I -At Large), education committee chairman, who called the recent reduction in private placements of public school students “a point of great suspicion for me.”

Under federal law, students with disabilities can be sent to private schools when the public system cannot adequately serve them, which has often been the case in the District’s long-troubled special-education system.

Gray (D) entered office in 2011 promising that he would improve the public schools enough to halve the number of such private placements from 2,204 to 1,102 by the end of his first term. He is on track to achieve that goal: As of last fall, fewer than 1,500 students were enrolled in private schools, according to documents Gray administration officials submitted to the council in February.

Further reductions in private placements will shrink how much the District must spend on private school tuition, from about $109 million in this year’s budget to $80 million next year, according to Gray’s proposed budget. The $30 million savings will be used to strengthen special-education programs in the city’s public schools, Gray administration officials said.

But advocates challenged that claim Monday. Nearly $7 million of the savings will go toward expanding public special-education services for babies and toddlers. But advocates said it appears the rest of the money will boost general funding for all students, raising questions about how and whether schools are prepared to receive more students with special needs.

Gray administration officials said schools have been receiving more money for special-education students since the per-pupil funding formula was adjusted two years ago to reflect the greater needs of children with disabilities. Officials said the push to bring students with disabilities back into the public schools allows those children to be educated, as required by federal law, in the “least restrictive environment.” The public schools also give those students exposure to the general curriculum and a wide range of peers.

“I think everyone can agree that students are better served by being in the schools with their peers and their communities,” Gray spokesman Pedro Ribeiro said.

Some parents say their children’s needs are being ignored because the government is intent on meeting the mayor’s mandate.

Greg Masucci said his son, a 5-year-old with autism, has regressed since enrolling in public school more than two years ago. The student was assigned a teacher with no special-education certification or experience, and the boy wandered away from school three times, Masucci said. Once, after the boy escaped from the playground, Masucci found him standing in a field adjacent to a busy road.

Masucci filed a complaint and formally requested a private placement, arguing that the school system was unable to serve his child. A hearing officer with the Office of the State Superintendent of Education denied the request.

“Thus far they haven’t even proven they can keep track of our son or keep him safe, and yet they claim everything is just fine and that he is progressing,” said Masucci, who called on the council to investigate whether the superintendent’s office is making placement decisions in the best interest of students.

Council member David Grosso (I-At Large) said the issue of private placements is “something we need to get a handle on.”

“This is about struggling families who need the government to perform at the highest level we can for them,” Grosso said.