When students return to school across the Washington area this morning, they will find teachers trained to recognize gang symbols, counselors coached to intervene more quickly with troubled students and police officers stationed in more high schools.

After a gang-related attack on a Montgomery County campus in early August, school administrators have ratcheted up efforts to ensure school safety, using PowerPoint presentations, back-to-school nights and workshops to reach out to teachers, parents and students.

Montgomery, which opens its schools today, will have a police officer at every high school this year, and the District will have 120 officers in its 17 high schools to guard against the violence that has erupted on campuses in past years.

In Fairfax County, where schools open next week, seventh- and eighth-graders will learn about the dangers of gangs in mandatory health classes. Arlington Public Schools will begin the discussions with some elementary students.

Even some communities with little sign of gang activity, such as Charles County, are taking time to brief teachers and principals about what types of graffiti, attire and tattoos could announce the arrival of gangs.

"Crime is transient. Criminals don't look at boundaries," said Capt. Michael Wyant of the Charles sheriff's office. "We're preparing our community to be able to deal with this."

At Springbrook High School, where two students were stabbed after summer school classes Aug. 5 in a gang-related attack in the parking lot of the Colesville area campus, Principal Michael Durso held a special meeting for parents last week to address concerns.

Durso, joined by officials from the police department and prosecutor's office, characterized the attack as an "isolated incident" but noted that the stabbings underscore the importance of being vigilant.

"What we hope to do following this is to make everyone aware but not overly alarmed," he said. "Springbrook will continue to be a safe and secure place."

Montgomery school officials said they will be sending a letter to parents this week discussing the stabbing incident, along with a tip sheet on gang awareness.

Gang members also are suspected in a stabbing at a Wheaton mall the same day as the Springbrook attack.

Last week, a federal indictment was brought against 19 men from Prince George's and Montgomery counties who are believed to be members of the Latino gang Mara Salvatrucha, also known as MS-13. The men are accused of six murders and four attempted murders between April 2003 and June 14. Suspected members of MS-13 also are facing charges for several incidents in the Virginia suburbs.

School officials in Arlington and Fairfax counties are taking steps to raise awareness by bolstering programs that help steer students away from trouble and by educating parents and school personnel about the warning signs of gang activity.

For the first time in Fairfax schools, lessons on the dangers of gangs -- including tips for avoiding overtures by gang members trying to recruit -- will be taught this year as part of the health curriculum, said P.D. O'Keefe, the system's violence prevention specialist. For the past several years, officers working in the schools had offered gang prevention lessons, but the program wasn't widely used.

"Every kid is at risk," said O'Keefe, a retired Fairfax police officer. "I have teachers call now and say, 'I have three kids I think are involved in gangs or flirting with gangs. What do I do?' "

School officials in Arlington are partnering with police and county officials to offer workshops for parents who want to spot signs that their children might be involved in a gang. And the oldest children in elementary school will begin talking about gangs during lessons on peer pressure and making choices.

In Prince George's, officials sponsored a regional school security conference this month that drew principals, school psychologists and counselors to discuss how to identify gangs and quell potential violence.

In addition, officials for several years have assigned at least one police officer to patrol every high school, a strategy that they say has helped law enforcement understand gang behavior before it becomes problematic.

Howard County high schools rely on police officers on campus to prevent crime and violence in schools where there is little evidence of gang activity. Still, the school system sent an administrator to a five-day workshop last year on recognizing and stemming gang activity.

"We watch really closely what happens in other districts," system spokeswoman Patti Caplan said. "It really does foreshadow what we see. . . . Sometimes, it really is a matter of time."

Charles County school resource officers will use PowerPoint presentations and fliers to tell teachers and principals the history of MS-13 and the behavioral changes that might signal that a student is becoming involved in a gang. The sheriff's department will highlight gang prevention at its annual back-to-school meetings, Wyant said.

In the District, police took over responsibility for school safety July 1. The police department is monitoring a two-year, $30 million contract for private security guards in the system's secondary schools.

In addition, D.C. Assistant Police Chief Gerald M. Wilson, a former Prince George's chief, is heading a new school security division that will place nearly 120 officers in the high schools. The officers and their supervisors will have a stronger ability to recognize problems, especially with the help of nearly 300 private security guards, and kick concerns up the chain of command, Wilson said.

At this point, most of the violence in the city's schools seems to spring from neighborhood feuds -- a student was fatally shot at Ballou Senior High School in February 2004, for example. But police are watching for evidence of Latino gangs.

Likewise, for Anne Arundel County schools, the concern isn't gangs so much as a perception that the safety of students, particularly in the high schools, has eroded in recent years.

In the school system's annual survey, the share of high school students who said they felt safe at school declined to 74 percent from 82 percent in 2004.

The superintendent and school board enacted several changes to improve security for the 2005-06 school year: Five high schools with discipline problems each will get an administrative trainee to focus on discipline. Security cameras, in place at five high schools, will be installed at two more.

Superintendent Eric J. Smith also has changed the rules for expulsions so that students can be removed for up to a full year, rather than one semester.

School security officials in Montgomery attended an all-day training session last week that included a presentation on how to identify students in a gang or at risk of joining one. The county will nearly double the number of uniformed police officers who work at middle and high schools in the system this year, from 13 to 24, with a Department of Justice grant. The change means that there will be an officer at all 24 active high schools, said Sgt. Tony Emanuel, coordinator of the program.

Ed Clarke, director of school safety and security for Montgomery public schools, said that for the first time, all principals will be briefed about the gang issue at a meeting next month.

Clarke said the goal this year is "to focus on greater awareness and identify students who might be a challenge."

Added Durso, the Springbrook principal: "Sometimes we've allowed ourselves to have a false sense of security because it was somewhere else. Now it's here, and we are dealing with it."

Staff writers Daniel de Vise, Maria Glod, Ann E. Marimow, Ylan Q. Mui, Nick Anderson and Clarence Williams contributed to this report.

Julian Matadi asks a question at a meeting for parents on gang violence at Springbrook High School. Springbrook Principal Michael Durso, left, with Jose Arroyo, called a recent attack outside the Colesville area school an isolated incident.