South Korea has conducted a series of civil defense drills. it says it is doing so to prepare for potential conflicts with the DPRK.

South Koreans stopped work on Wednesday afternoon, putting on gas masks instead, and heading to underground shelters. This is the country's biggest civil evacuation exercise since such training first started in 1975.

As air raid sirens blared across the nation, government officials and company employees left their posts, taxi drivers parked their cars along downtown streets, and housewives turned off the gas to evacuate to underground shelters.

A dozen fighter jets flew across the sky to simulate air strikes, while a bullet train began running at dramatically lower speeds. Authorities expected up to 10 million of the country's 49 million people to take part in the 20-minute drills.

This is South Korea's first nationwide civilian evacuation exercise against possible DPRK attacks. Similar drills have been regularly conducted over the last six decades, but only in a limited number of strategic towns.

Kim Ye-jI, Middle School Student, said, "This drill was very helpful because we learned what to do in certain situations if a war occurs."

Park Yeon-Soo, Director of National Emergency Management Agency, said, "This exercise is meaningful, in that it's taking place at this time when war threats are actually becoming real."

Kim Hwang-Sik, South Korea Prime Minister, said, "When there's a sudden provocation from the DPRK, it will help people learn how to react by actually experiencing it."