Police are set to enforce the highest-level security alert in the country’s three-tier system on June 3 to prevent violence and maintain peace when voters head to the polls to choose their next president.

Acting National Police Agency Commissioner Lee Ho-young on Thursday announced the plan for the “gapho” alert while presiding over an online conference of police officials from the Seodaemun Police Station in Seoul.

This emergency alert will allow the agency to mobilize 100 percent of its forces and put all police officials on standby, with commanders ready to give orders.

Police will strengthen their security posture starting Monday, when the official campaign period kicks off, and increase vigilance when the two-day early voting period begins on May 29.

About 168,000 officers are expected to be mobilized to protect candidates, polling stations and counting stations, and to prepare for any contingencies.

Lee called on authorities to ensure that the upcoming presidential election is fairer and more orderly than any other election in history, through tight security and strict enforcement of the law, and warned that police will respond sternly to election crimes.