The trip by Lee Hee-ho, the 90-year-old widow of late South Korean President Kim Dae-jung, and Hyundai Group Chairwoman Hyun Jeong-eun follows a warning by North Korea that Seoul's attitude toward condolences could affect the future course of inter-Korean relations.

"I hope that our trip to North Korea will help improve relations between South and North Korea," Lee said in written a message read by her aide before crossing the border with 17 other delegation members.

Tensions still persist on the Korean Peninsula over the North's two deadly attacks on the South last year.

South Korea expressed sympathies to the "people" of North Korea over Kim's death and has allowed civilians and private organizations to send messages of condolence to the North.

Seoul decided not to expand civilian delegations, however, beyond those of Lee and Hyun who both have ties with North Korea, though the North has said it will accept all condolence delegations from South Korea.

South Korea made the exception because North Korea sent separate condolence delegations to Seoul after the deaths of President Kim Dae-jung, Lee's late husband, and Chung Mong-hun, Hyun's late husband and former Hyundai Group chairman.

Kim Dae-jung held a landmark summit with Kim Jong-il in 2000 while Chung pushed joint venture economic projects with North Korea.

The two delegations led by Lee and Hyun are scheduled to hold a luncheon meeting with unidentified North Korean officials in Pyongyang later Monday before paying their last respects to Kim, according to the Unification Ministry, which handles inter-Korean affairs.

Kim, who ruled the communist nation with an iron fist, died of heart failure on Dec. 17 at the age of 69, according to the North's state media.

The two delegations are scheduled to return home Tuesday prior to a state funeral set for Wednesday. The North has said it will not accept foreign delegations at the state funeral.

The trip has raised guarded hope, however, that Lee and Hyun may meet with North Korea's new leader Kim Jong-un, the youngest son of the late leader, during their stay in Pyongyang in what could be Kim's the first encounter with South Koreans.

Asked whether the delegations hope to meet with the North's young leader or whether they carry a government message, Lee's aide stressed that the trip is purely for offering condolences.

On Sunday, the North's Committee for the Peaceful Reunification of Korea criticized the South Korean government for attempting to "quench the hot wind for condolatory visits."

"Their obstructions will entail unpredictable catastrophic consequences to the North-South relations," the committee said.

"The nation will finally test the morality of the South Korean authorities as well as sincerity of their call for improvement of the North-South relations."

In 1994, South Korea neither expressed condolence nor sent an official delegation over the death of the North's founder Kim Il-sung, the father of late leader Kim Jong-il.

The two Koreas are technically at war since their 1950-53 Korean War ended in a truce, not a peace treaty.