Three Arlington public high schools are increasing security measures after a intrusion incident in Yorktown last week.

Starting this week, students at Yorktown, Wakefield and Washington-Liberty high schools will be required to present pre-approved identification to staff members to enter school buildings. Accepted forms include school-issued photo IDs, StudentVue accounts, and government-issued IDs such as a driver’s license.

The new requirement comes about a week after a former student allegedly entered Yorktown High School, prompting a significant police response and charges of trespassing.

Jim Miller, assistant director of safety, security and emergency management for Arlington Public Schools, says the move is a response to the changing “threat landscape,” which includes false alarms at the bomb, threats on social networks and crushing Incidents in which people attempt to get a police SWAT team to show up at a location where there is no emergency.

“For us, this was a natural progression… we are simply putting in place an additional level of security and controls to ensure our schools are safe in the morning and throughout the day.” Miller told ARLnow.

Yorktown was the first school to implement the new system, which came into effect yesterday (Wednesday). Miller says Washington-Liberty and Wakefield plan to begin requiring the same forms of identification starting tomorrow (Friday).

So far, Miller said things are going well in Yorktown.

“It was pretty routine,” he said. “In fact, there was no impact on the finish. Students were able to move around the school as if it were a normal day.

Miller noted that students who forget their ID will still be allowed to enter the building after verifying their identity via their Social Security number, student ID number or a quick name search.

It is unclear whether the new system will be permanent or temporary. For now, the APS is taking a wait-and-see approach.

“We’re going to try to figure this out, see how it works, see what the impact is on staff, etc.,” Miller said. “There are a lot of factors we have to evaluate. We will evaluate after a few weeks and determine whether or not this will last longer term.