Two private South Korean delegations have crossed the heavily fortified border into North Korea to pay respects to its late leader Kim Jong Il, who died December 17.

The delegations were led by the widow of former South Korean President Kim Dae-jung, who held a landmark summit with Kim Jong Il in 2000, and Hyundai Group chairwoman Hyun Jeong-eun, whose late husband had ties to the North.

South Korea is allowing only the two groups to visit and pay condolences for Mr. Kim's death. They will not stay for the late leader's Wednesday funeral.

Pyongyang accused Seoul of preventing other South Koreans from crossing the border to pay respects, and warned the move could strain relations between the two countries.