Students headed back to school across the Washington area Monday and were greeted with teachers trained to recognize gang symbols, counselors coached to intervene more quickly with troubled students and police officers stationed in more schools.

Students at the Peabody Elementary School on Capitol Hill got a handshake from Mayor Tony Williams, who toured the school's newly painted hallways and art room. The D.C. mayor looked in on one classroom to wish the students good luck in their new school year.

A security guard also greeted the Peabody students. Contract security guards and police officers will be stationed at schools in the District this year to guard against the violence that had erupted on campuses in past years.

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

Montgomery will also have a police officer at every high school this year.

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 County 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.

In Howard County, gangs have not made the inroads that they have in Montgomery and Prince George's counties. But all of Howard's 12 high schools had police officers stationed on campus.

Staff writer Ylan Q. Mui contributed to this report