Seoul City said on Friday that it will hold the annual Ulchi civil defense exercise next week for a four-day run. 

The exercise, which will kick off on Monday, will conduct drill scenarios reflecting North Korea’s threats of drones and launches of trash-carrying balloons, involving some 140-thousand people from about 170 city organizations.

The Ulchi drills are a nationwide exercise held once a year to review and supplement the government’s preparedness and contingency plans for a national emergency such as war, and to familiarize public officials with the procedure of their duties in such an event.

The four-day exercise will include a drill on taking measures for a wartime situation, discussions of wartime tasks, and joint counterterrorism. 

An anti-terror exercise at public facilities will be held at the Olympic Gymnastics Arena in southern Seoul on Tuesday, and a civil defense drill is scheduled for 2 p.m. Thursday, which will feature air raid sirens and public alerts for evacuation and traffic control.