South Korea staged the country's largest evacuation drill Wednesday amid renewed fears of a war on the divided Korean peninsula.
In preparation for possible new attacks by North Korea, South Koreans stopped their cars, donned protective masks, and raced to underground shelters.
The National Emergency Management Agency expected up to 12 million people to participate in the training.
"The drill is about taking shelter at a time of an attack, with close relations among local residents, government offices, and firefighters," Park Chung-Wung, chief commander at the National 119 Rescue Services, told Xinhua News.
"We will need these evacuation plans and skills sooner or later in case war breaks out, and I think war can happen any time," 16-year-old South Korean resident Han Yoo-jin said.
Wednesday's 20-minute drill came almost one month after the two nations exchanged fire across the tense western sea border. The skirmish was provoked by North Korea's artillery bombardment of South Korea's Yeonpyeong Island, Nov. 23.
The artillery barrage was the North's first assault on a civilian area since the two nations signed an armistice in 1953.