St. Paul teachers took a preliminary step toward a strike Tuesday night as frustrations over student behavior began boiling over.

Earlier in the day, Ramsey County Attorney John Choi charged a 16-year-old Central High School student with felony for an alleged assault on a teacher and called for a task force to address growing violence in the schools.

Denise Rodriguez, president of the St. Paul Federation of Teachers, said in a statement Tuesday night that the union is trying through contract negotiations to “make our schools safe for students and staff and to end the racial predictability of disciplinary outcomes.”

They want more social workers, counselors, nurses and school psychologists, greater parent engagement and smaller class sizes in order to build relationships between teachers and their students and families.

But St. Paul Public Schools administrators so far have opposed the union’s proposal for “school climate improvement teams” in individual schools.

So on Tuesday, Rodriguez said, the union filed a petition for state mediation, which is an initial step toward a strike vote.

“Teachers don’t want to walk away from their classrooms or their students but if our school climates are not safe and equitable environments for learning, that is a step our members may need to take. We can wait no longer,” she said.

Earlier, Choi and schools Superintendent Valeria Silva held a joint news conference to address violence in the schools, sparked by Friday’s assault on a Central High teacher and assistant principal.

It was the 27th time a school staffer has been assaulted in Ramsey County this year. Such incidents “have been increasing at a really alarming rate,” Choi said. He said he and Silva are working to launch a task force to address the growing problem, which he called a public health crisis in need of intervention.

“Schools cannot do this alone,” Choi said. “I think oftentimes we as a community make the mistake to say these problems belong in our schools and need to be solved with our school leaders and teachers. But the reality of it is, I really believe, they really need our help and they can’t do it alone. They need the help of the parents, and that starts at home with them. But it also includes the community.”

At Central on Friday, 16-year-old Fon’Tae O’Bannon had joined in a fight that began in the lunchroom between two other males, according to the criminal complaint filed Tuesday in Ramsey County Juvenile Court. When a teacher and administrator tried to stop the fight, O’Bannon allegedly lashed out.

Witnesses saw O’Bannon throw science teacher John Ekblad against a wall and onto a table, according to the criminal complaint. O’Bannon then choked the teacher as he lay on the ground until he lost consciousness, the charges said.

When assistant principal Mark Krois arrived, O’Bannon threw him into a wall, the complaint said.

As the assistant principal was trying to pull O’Bannon off the injured teacher, O’Bannon’s 15-year-old brother yelled profanities at the principal and punched him several times in the chest, according to a police report.

O’Bannon is charged with felony assault, gross misdemeanor assault and obstructing the legal process.

The 15-year-old, who was identified in the complaint as FO but whose name has not been released because of his age, was charged Monday in juvenile court with fourth-degree assault and obstructing the legal process.

When the school resource officer went to help Krois, the principal told him to help Ekblad, who had been hurt, the charges said.

The officer went to find Ekblad, but “O’Bannon charged at the officer,” the complaint said. “The (officer) grabbed O’Bannon’s arm but had a hard time controlling him. O’Bannon continued to struggle, told the officer to ‘get the (expletive) out of my face’ and attempted to run away.”

The officer called for backup and O’Bannon was arrested. “O’Bannon began to laugh,” the criminal complaint said. He denied he had assaulted any staff.

Ekblad was hospitalized and diagnosed with a concussion and traumatic brain injury.

Both teachers remain on leave and are being allowed as much time as they need to recuperate physically and emotionally, Silva said. Ekblad is no longer in the hospital, she said.

The two boys were new to Central this fall, but had been in and out of St. Paul schools over the years.

The older brother, Fon’Tae O’Bannon, was a junior running back for the school’s football team. He sat out part of the season due to a paperwork error during his transfer to Central.

Silva wouldn’t comment on the status of the students, but said disciplinary actions could include suspension or expulsion.

The last student to be expelled from St. Paul public schools was in October 2009; Silva became superintendent in December of that year. Asked why there have been no expulsions in recent years, Silva said each incident is reviewed and remedied individually and sometimes parents opt to voluntarily withdraw their children from the school.

Silva couldn’t say exactly what caused the uptick in assaults on educators, and said the students involved often have no prior history of violence in school, which can make it hard to anticipate behaviors. The brothers involved in Friday’s fracas, for example, did not have prior discipline histories, she said.

“I know we are living in a very difficult society today, and our kids are, many of them, are going through tough times,” Silva said. “But … we don’t want them to use violence to resolve their issues. We as a system are building as many prevention strategies as we can, but we cannot always prevent or predict.”

Training is provided to school employees on mediation and de-escalating conflict, including proper restraint methods, Silva said.

Both she and Choi said schools need to remain nonviolent sanctuaries focused on learning, but both acknowledged that the growing incident numbers cannot be ignored.

Choi said the problem is not limited to St. Paul. Of the 27 assault incidents that resulted in charges this calendar year in Ramsey County, about 50 percent occurred in St. Paul schools, with the other half in suburban schools, he said.

Choi believes the violence is related to the broader issue of how children — particularly boys — are being raised and socialized. “The work that I’ve done with kids in our community, with kids who are at risk or who are in the system, I can tell you a lot of these kids are survival-based kids,” he said. “They’ve gone through immense trauma in their lives, and they’re dealing with all of that at home — and their parents might be as well.”

A string of incidents in local schools this school year involved weapons on campus, fighting among students and the use of stun guns and chemical irritants by police officers.