North Korea's top official in charge of inter-Korean affairs made a secret visit to Seoul ahead of the second summit between the leaders of the rival Koreas in 2007, a former South Korean spy chief said in a memoir released Thursday.

Kim Yang-gon met with the then-President Roh Moo-hyun at Cheong Wa Dae, South Korea's presidential office, on Sept. 26, according to the memoir of Kim Man-bok, who headed the National Intelligence Service from 2006 to 2008.

The meeting took place five days before Roh walked across the border into North Korea for talks with the then-North Korean leader Kim Jong-il, the late father of the current leader Kim Jong-un.

Kim Jong-il also held summit talks with Roh's predecessor, Kim Dae-jung, in Pyongyang in June 2000 -- the first inter-Korean summit between the two sides still at war after the 1950-53 Korean War ended in a truce, not a peace treaty.

A landmark deal reached in the first summit paved the way for the two Koreas to ease military tensions and begin economic cooperation after decades of hostility.

Kim Jong-il, however, told Roh in 2007 that the deal reached in the 2000 summit had become "empty rhetoric" and claimed South Korea did not show an independent attitude in resolving military hostilities between the two Koreas, according to the memoir.

In return, Roh told Kim Jong-il that it is impossible for any government in South Korea to sever its relations with the United States overnight, noting South Korea has been relying on the U.S. and it is true that South Korea is pro-American country, the book said.

About 28,500 U.S. troops are stationed in South Korea as a deterrence against North Korea.

The memoir also said Kim Jong-il was negative to Roh's idea of creating a Yellow Sea peace zone along the disputed sea border before eventually accepting the proposal after some persuasion by Roh.

The sea border, known as the Northern Limit Line, is the scene of a series of bloody naval clashes between the two Koreas.

In 2007, Roh and Kim produced a deal calling for the massive investment from the South into the North's key industrial sectors, including shipbuilding and tourism.

North Korea has routinely pressed South Korea to honor agreements reached at two previous summits in 2000 and 2007 and made Seoul's implementation a key condition for better ties.

The memoir, which was co-authored by South Korea's then-point man on North Korea Lee Jae-joung and former presidential security adviser Baek Jong-chun, is set to hit bookshelves on Friday. (Yonhap)