"The trial runs will be implemented simultaneously in the North and South on May 25," a spokesman for South Korea's unification ministry told AFP.

About 100 North Koreans, including engineers, government officials and journalists will ride from Kaesong in the North to the South Korean city of Munsan on 27.3 kilometers of newly laid track.

Meanwhile, a similar number of South Koreans will travel in the opposite direction on a 25.5-kilometer stretch from South Korea's Donghae to Mount Kumgang in the North.

The agreement was hammered out at talks in Kaesong that ended early Saturday with the two sides still undecided on when to hold an official ceremony to celebrate the opening of the landmark links.

Former South Korean president Kim Dae-Jung has said he wants to travel by train when he heads north for talks with North Korean leader Kim Jong-Il in mid-June.

The agreement, which is part of a series of reconciliation projects between the two Koreas, comes with the Stalinist North still refusing to defuse a stand-off with the United States over its nuclear weapons programme.