patrolling
v.v. moving around an area to keep it safe or to make sure everything is okay. You often see police or guards doing this in public places.
v. moving through an area at regular intervals for the purpose of security, observation, or maintenance of order. Present participle of 'patrol'; describes the active process of monitoring a perimeter or zone.
Security guards are patrolling the mall tonight.
The coast guard spent the entire weekend patrolling the shoreline to ensure that no small vessels were in distress during the storm.
By patrolling the border with increased frequency, the authorities hoped to deter illegal crossings while simultaneously providing a visible presence to reassure the local residents of their safety.
Typically used as a transitive verb taking a direct object (the area being monitored), or intransitively to describe the general activity.