WASHINGTON — While prosecutors dropped rape charges against two Montgomery County students, a security review found that all but the county’s three newly built high schools could stand security improvements.

Work this summer will enhance security at 22 public high schools. The school board has approved more than $1.5 million toward improvements that include security gates, lock changes and, in some cases, new doorways to secure corridors.

The scope of these improvements will vary from school to school.

These enhancements are the result of a security review prompted by the March rape allegation against two Rockville High School students. Prosecutors later dropped charges in the case.

“Our primary objective here is to enhance the current security measures that are already in place,” said James Song, facilities manager. “It will provide better control of interior spaces as well as extra spaces or certain sections of the building, both during and after school hours.”

As they are relatively new, Gaithersburg, Paint Branch and Wheaton high schools aren’t subject to the upgrades.

The majority of the upgrades are expected to be completed this summer, with the rest done in the fall.

Officials added that continual evaluations will be made moving forward — and will include input from school staffers.

The district also plans a review of middle and elementary schools.