An F/A-18C Hornet with Marine All-Weather Fighter Attack Squadron 224 takes off from Suwon Air Base, South Korea, Aug. 7, 2024. (Calah Thompson/U.S. Marine Corps)

Two Chinese teenagers were arrested last month on suspicion of illegally photographing military aircraft at a South Korean air force base, a police investigator said Tuesday.

The pair were detained around 3:30 p.m. on March 21 near Suwon Air Base, approximately 20 miles south of Seoul, after a resident reported seeing them filming aircraft, a Gyeonggi Nambu Provincial Police investigator said by phone.

It’s customary in South Korea for some government officials to speak to the media without providing their names.

Police seized two mobile phones and two digital cameras from the teens, the investigator said. Images of military aircraft taking off and landing were found on the devices and are under investigation, he added.

The teenagers told authorities they are aviation hobbyists visiting South Korea. They were released after questioning but remain barred from leaving the country until the investigation concludes, the investigator said.

Prosecutors, not police, decide formal charges under South Korea’s justice system.

Filming military installations in South Korea without authorization can carry a penalty of up to three years in prison or a fine of approximately $20,400 under South Korean law.

F-16 Fighting Falcons used the Suwon runway last month during Freedom Shield, a joint U.S.-South Korea military exercise, according to images released by the 51st Fighter Wing. However, no 7th Air Force aircraft were present at the base on the day of the arrests, spokeswoman Maj. Rachel Buitrago said by email Tuesday.

The incident follows a similar case in July, when three Chinese students were investigated for allegedly flying a drone near Busan Naval Base to film the aircraft carrier USS Theodore Roosevelt shortly before the start of the Freedom Edge exercise with the U.S., South Korea and Japan.