Baltimore principals will be required to take extra steps before suspending 4- and 5-year-olds under a new policy that seeks to curb the practice of kicking the youngest students out of school.

Beginning next school year, principals will have to consult with the central office before they suspend pre-kindergarten and kindergarten students for any length of time — a move that comes after The Baltimore Sun revealed a sharp uptick in pre-K suspensions in Baltimore, which had the most of any district in the state.

The little-known and controversial practice, which some education advocates say is too extreme for toddlers, was tackled by new schools CEO Gregory Thornton at his first school board meeting this week.

Thornton, who took the helm of the district July 1, said he believes students need to be supported rather than suspended, except in cases where they pose a danger to themselves or others.

"When a youngster becomes unsafe, that youngster needs to be removed," Thornton said, adding that he has suspended elementary school students who possessed weapons.

He said he once had a rule against suspending 4- and 5-year olds — until he witnessed a disruptive student in action.

"I watched a 5-year-old turn a classroom out," Thornton said. "He needed to go home. I didn't believe it until I saw it."

He said, however, that he also believes school leaders across the nation are grappling with how to deal with young children who have behavioral problems.

He said educators need to better prepare for students entering the system with problems that could affect their adjustment to an educational setting, and he believes it is educators' responsibility to figure out the root causes of a child's disruptive behavior.

In the 2012-2013 school year, the district noted 33 suspensions of 25 pre-K students, meaning some students were suspended more than once. The district declined to provide a breakdown of the offenses.

Across the state, 77 pre-K students were suspended, primarily for physical attacks on staff and other students. Legislators formed a statewide task force to study the issue.

The city had 181 kindergarten suspensions that year, a decrease of 24 percent after increasing for several years. It was the most kindergarten suspensions in the state.

Suspension data for the most recent school year will not be released until August, officials said.

City school officials said they believe that consultation with the central office will help principals explore whether a suspension for actions such as throwing blocks is the most developmentally appropriate sanction for a young child, or whether a student's behavior warrants further investigation.

"It's a principal's job to know their student," said Everett Garnett, director of suspension services.

Jimmy Gittings, president of the principals union, said he has minor concerns about the new policy because it further hinders principals' ability to make the best decision for their schools.

The principals union has complained that principals have increasingly been limited in their power to suspend students amid the campaign to reduce suspension numbers.

Currently, principals need to consult with the central office only to suspend a student for more than 10 days.

"I'm concerned that more autonomy is being taken away from our principals," Gittings said.

Maryland has been at the forefront of national conversations about eliminating "zero-tolerance" policies in student discipline.