Nothing is ever easy for the rival Koreas, even that most ubiquitous and usually innocent of Olympic interactions, the selfie.
Like dozens of athletes at the Rio Games, gymnasts Hong Un Jong of North Korea and Lee Eun-ju of South Korea met on the sidelines during competition and training.
The 17-year-old Lee, who is at her first Olympics, posed Thursday for the smiling selfie with Hong, a 27-year-old veteran. That friendly encounter and others between the two were captured by journalists — and immediately took on larger significance for two countries still technically at war.
Hong became the first female gymnast from North Korea to win a gold medal in 2008, when Lee was 9 and living in her native Japan. Lee moved to South Korea in 2013 because her Korean father wanted her to learn more about the country's culture.
A few days after the selfie was taken, Lee and Hong interacted again Sunday while on the floor at the same time during preliminary competition. Lee was eliminated, while Hong will compete in the vault final.
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Photos of their warm moments delighted many South Koreans and provided a rare note of concord in otherwise abysmal relations between the rivals. Such meetings are not illegal in South Korea, but they are complicated by the two countries' long history of animosity and bloodshed.
The Korean Peninsula is still technically in a state of war because there has been no peace treaty signed to officially end the 1950-53 Korean War. Nearly 30,000 U.S. troops are stationed in South Korea as a deterrent against North Korea, and the neighbors regularly trade insults and warnings of war, including recent threats from the North of missile strikes on Seoul and its ally, Washington.
A web of laws, most left over from the days when the South was ruled by a dictatorship, govern how South Koreans are supposed to interact with North Koreans. Travel and communication are severely restricted; even praising the North is illegal in the South.
South Koreans are required by law to obtain government permission for any planned meeting, communication or other contact with North Koreans.
This requirement is waived for spontaneous interactions with North Koreans that can happen during foreign travel, like the Olympics. But South Koreans must still provide an account of what happened to the South Korean Unification Ministry, which handles inter-Korean issues, within seven days, according to the ministry.
So while it's OK for South Korean athletes to talk to the North Koreans they meet at the Olympics, they must later submit reports about the encounters to their Olympic committee, which will then pass the information to the government.
These brief, friendly moments between North and South Korean athletes may not seem to be a big deal to outsiders, but they often stimulate deep emotions on the Korean Peninsula, which has been divided by the world's most heavily armed border for decades and where many long for eventual reunification.
Inter-Korean ties, never good, have been terrible in the past decade of conservative rule in the South. But there were friendlier days under previous liberal governments in Seoul, and they were often seen most clearly in sports. North and South Koreans, for instance, marched together under a flag that symbolized unification during the 2000 Sydney Olympics.
Whatever happens in politics, many South Koreans love seeing their athletes treating North Korean competitors with respect, and there's always lots of media attention on these moments of harmony.
When North Korea's women's soccer team won gold at the 2014 Asian Games in Incheon, South Korea, and the South won bronze, many South Koreans expressed delight in seeing players from both countries celebrate together after the medal ceremony, smiling and putting their arms around each other.
Similarly, the Rio Olympic selfies represent a small thaw in otherwise frigid ties — just as long as it's all reported to the authorities.
AP writer Kim Tong-hyung contributed to this story from Seoul, South Korea.