Hundreds of South Koreans crossed the border to North Korea on Saturday for the second and final round of reunions of families separated by the 1950-53 Korean War.

About 250 South Koreans, many of them over 80 and some in wheelchairs, made their way through an immigration office at the world's most heavily fortified border. They will travel by bus to the North's scenic Diamond Mountain resort for three-day meetings with their North Korean relatives most hadn't heard from for more than 60 years.

At least two traveled to the North in ambulance vans because of their fragile health.

In the first round of reunions earlier this week, about 350 South Koreans traveled to the mountain resort to reunite with 180 North Korean relatives.

The highly-emotional reunions, which are held irregularly between the rivals, double as a reminder that the Korean Peninsula is still in a technical state of war because the Korean War ended with an armistice, not a peace treaty.

Before the current reunions, about 18,800 Koreans had participated in 19 face-to-face reunions held between the countries since 2000. The Koreas ban ordinary citizens from visiting relatives on the other side of the border or contacting them without permission.

South Korea uses a computerized lottery system to pick participants for the reunions while North Korea reportedly chooses based on loyalty to its authoritarian leadership.

Nearly half of the 130,410 South Koreans who have applied to attend a reunion have died.