New York City is keeping far too many preschoolers with disabilities in isolated classes, according to state officials, who are increasing the pressure on the city to change its approach.

Nearly 47 percent of three- and four-year-olds with special needs in the city attended classes exclusively with other students with disabilities last school year. That rate is the highest in the state, where an average of 31 percent of preschool-aged children were in special-education classes.

Part of the reason for the city’s high segregation rate is that it has typically sent pre-kindergarten students who need intensive services to private programs, since regular pre-K sites often have not had the capacity to meet their needs. Given a growing body of research that suggests inclusion benefits students with disabilities, city and state officials both say they want fewer preschool students with disabilities sent to separate programs.

“New York City does place a large percentage of their youngsters in special programs that serve exclusively students with disabilities,” said James DeLorenzo, the state education department’s special-education chief. “I think that’s an area that’s ripe for us to work more strategically to address.”

State education officials pointed out the city’s inclusion rates in Albany this week during a presentation about sweeping plans to improve special education across the state. They intend to ask certain districts for more details about how they assign students with disabilities to classes.

Meanwhile, New York City officials say they are creating more classes that serve a mix of students and without special needs as part of the city’s broad expansion of pre-kindergarten. The city has also added extra teams to screen more pre-K students for disabilities, according to Harry Hartfield, a spokesman for the city education department.

The efforts are propelled by research that suggests that many students with disabilities benefit from mixed-ability classes starting at an early age.

“Whenever possible, a preschooler should learn alongside typically developing peers,” said Randi Levine, early childhood education project director at Advocates for Children, a group that provides free legal services for students. “The expansion of pre-K in New York State and New York City provides an opportunity to do that, but it’s only possible with appropriate resources and training.”

The state’s proposal, which officials presented Monday to the Board of Regents, would require New York and other districts to submit plans for how they will enroll more preschool students with disabilities in general-education classes, along with annual reports on their progress. A separate proposal would require similar plans for integrating older students.

In addition, the state education department is planning to host a series of meetings in New York City among city officials and educators to discuss why so many pre-K students attend separate special-education programs and how that can be fixed, according to DeLorenzo, the assistant state education commissioner.

New York has long struggled to integrate students with disabilities into general-education classes whenever appropriate, a federal mandate known as placing students in the “least restrictive environment.” The state’s record of making such placements ranked second worst in the nation in the 2013-14 school year, according to state officials.

The city’s education department launched a system-wide effort to address this problem in 2012, overhauling its policies so that the majority of special-needs students are now expected to enroll in their local schools and take general-education classes as often as possible. As a result, 91 percent of students with disabilities attended their local schools last year, up from 85 percent in 2011, according to the city.

With the changes already underway in new pre-K classes, the city expects more pre-K students with disabilities to learn alongside their non-disabled peers in the coming years, said Hartfield, the city spokesman.

“We will continue to work to ensure that, whenever possible, students with disabilities can receive the high-quality education they deserve in their local school,” he said in a statement.

While advocates have applauded the push for integration, they have also warned that many local schools and general-education teachers are unequipped to meet the needs of many students with disabilities.

Jean Mizutani, a program manager for the nonprofit INCLUDEnyc, a support agency for young people with disabilities, said the new focus on preschool is a continuation of this effort to better integrate disabled students with their non-disabled peers. The idea makes sense, she said, yet she doubts the city has enough pre-K teachers who are adequately trained to serve students with special needs.

Placing those students in a general-education class “is the easy part,” Mizutani said. “To get them participating, to have them learning in a constructive way, is another thing.”