North Korean leader Kim Jong Un’s sister paid a rare visit to the country’s militarized southern border to deliver a condolence message over the death of a former South Korean first lady who promoted unity between the rivals.

Kim Yo Jong extended the offering Wednesday to South Korea’s national security adviser, Chung Eui-yong, at the Panmunjom truce village that straddles the border, a presidential spokesman in Seoul said. It was a gesture of appreciation for Lee Hee-ho, the wife of former President Kim Dae-jung, who died Monday at the age of 96.

North Korea’s government has had a special relationship with Lee Hee-ho and Kim Dae-jung, who was awarded a Nobel Peace Prize for his “Sunshine Policy” of rapprochement to coax the reclusive state out of its shell. This resulted in him traveling to Pyongyang in 2000 with Lee for the first summit of the leaders of the two Koreas. He and North Korean leader Kim Jong Il shared hugs, held hands and sang traditional songs together.