Olympic athletes from North Korea are under intense surveillance from their own nation's security forces under fears they will defect to their southern neighbor, according to CNN's Paula Hancocks and Taehoon Lee.

Nearly 500 North Koreans - a group that includes not only athletes, but also officials, media, cheerleaders, and security staff - have traveled to South Korea for the Olympics.

Though North Korean athletes have occasionally defected at international competitions in the past, it appears unlikely to happen in PyeongChang as the North Korean delegation is subject to round-the-clock surveillance, a former North Korean police officer told CNN.

He noted delegates won't even be permitted to use the bathroom alone.

Athletes from North Korea marched alongside athletes from South Korea at the opening ceremony, and the two nations will unite to form a single joint team for the women's hockey tournament.

With diplomatic relations between the North and South greatly improved at the moment, there is some hope the Olympics will be the catalyst that leads to eventual reunification of the Koreas.