Mayor Bill de Blasio and Chancellor Carmen Fariña announced long-awaited revisions to school discipline policies on Friday, including new suspension procedures and restrictions on school-based police officers.

The plan includes a new review process for suspensions for insubordination, restrictions on handcuffing students, and expanded training for the city’s School Safety Agents. The changes came as the city faced mounting pressure to further revamp its discipline code given the disproportionate suspension rates of black and Hispanic students and students with disabilities, which city officials have said they are committed to improving.

“Today’s changes will protect students from bullying and violence, and provide relief and a better school experience for students who need to be focused on their learning and not constantly worry about getting suspended for any minor incident,” Chancellor Fariña said in a statement.

Suspensions are down 27 percent since 2011, and in-school arrests have dropped 32 percent between 2012-13 and 2013-14, according to city statistics. But black and Hispanic students account for 90 percent of suspensions but just 70 percent of city students, while students with special needs account for about one-third of suspensions.

Under the new policy, principals will be required to obtain written approval from the department’s Office of Safety and Youth Development before suspending a student for defying authority, a move likely to reduce suspensions for less significant offenses. The more severe superintendent’s suspensions are being no longer an option for students involved in “minor physical altercations.”

The city’s changes are less drastic than those made by a few other large cities in recent years. Both San Francisco and Los Angeles have eliminated schools’ ability to suspend students for “willful defiance,” and there has been a nationwide push to roll back zero-tolerance discipline policies, which favored severe penalties for minor infractions.

The changes came as a disappointment to advocacy groups, who wanted the city to eliminate suspensions for “defying authority” and bar school safety officers from being able to arrest or ticket students for misbehavior. In a sign that there could be more changes coming, de Blasio and Fariña created a “School Climate Leadership Team” that includes advocacy groups.

“We’re hopeful about the creation of the mayor’s leadership team, and think that could help us pave the way for new discipline policies,” said Shoshi Chowdhury of the Dignity in Schools campaign.

Principals have long cautioned that it’s not simple to remove a tool for dealing with unruly students, like suspensions, especially if schools don’t get any additional training or resources.

The city is allocating $432,000 in new money for the changes, officials said, to expand an algebra-based mentoring program from four to six schools next year. The programs will cost $5 million overall, though that money is already being spent.

The City Council will continue providing funding to train school staff in “restorative justice” practices, which include peer mediation and student panels that try to change students’ behaviors. Supporters say that those programs can help create a positive environment and offer a more productive way of dealing with disruptive students, though they take significant effort to implement fully.

“We have a lot of schools interested in changing their discipline policies, but they know it takes money, staff, and training time,” said Urban Youth Collaborative coordinator Kesi Foster.

The changes are the latest in a series of recent edits to the city’s discipline and suspension policies, but the first under the de Blasio administration.

Calls for changes to the suspension policy grew louder when the city began reporting suspension statistics in 2012. A coalition of advocates led by retired Chief Judge of New York Judith Kaye made recommendations for changes in 2013, and the discipline code—which outlines the city’s school discipline policies and students’ rights—has changed over the last few years to emphasize alternatives to suspension.

The package of changes announced Friday includes new training and restrictions on School Safety Agents and police officers assigned to schools, who man metal detectors and patrol the halls of city schools. (The city’s 5,000 safety agents together make up one of the largest police forces in the country, and report to the police department, not the principals in their buildings.)

And after advocacy groups publicly voiced their frustrations in October about reports of children as young as five being restrained in schools, the discipline code now says that students under age 12 will not be handcuffed. The police department will also start providing monthly reports on how often students are restrained.

The revised code includes more information on how schools can address bullying and changes to rules about calling 911 for help dealing with disruptive students. The city settled a lawsuit in December requiring the Department of Education to come up with a formal plan for dealing with disruptive students that didn’t involve calling 911, which often resulted in students being sent to the emergency room though they had no medical issues. The city is now proposing that each school be responsible for developing a guide for when a student’s behavior warrants calling 911.

The proposed changes to the discipline code will be discussed at a March 2 hearing and will go into effect this spring.

Sarah Darville contributed reporting.