SEOUL, Jan. 29 -- Former South Korean President Lee Myung-Bak disclosed behind-the-scene talks with the Democratic People's Republic of Korea (DPRK) for a summit during his presidency with late DPRK leader Kim Jong Il, Yonhap News Agency reported Thursday, citing Lee's book set to be released next week.

Lee said in his book titled "President's Time," an 800-page autobiography on his five-year presidency from 2008 that the DPRK began to express its willingness from late 2009 to hold inter- Korean summit, which was not materialized as Pyongyang demanded a huge scale of economic assistance. The book is scheduled to be released on March 2.

In October 2009, former South Korean Labor Minister Lim Tae-hee met Kim Yang Gon, director of the DPRK's United Front Department in charge of Seoul-Pyongyang relations, in Singapore. Kim called for huge economic assistance from Seoul to create an atmosphere for inter-Korean summit.

In November, South Korea's Unification Ministry and the DPRK's United Front Department held working-level contacts in Kaesong, just north of the heavily fortified inter-Korean border and a home to the joint industrial park between the two Koreas.

During the working-level meeting, the DPRK demanded 100,000 tons of corn, 400,000 tons of rice, 300,000 tons of fertilizers and 100 million U.S. dollars worth of asphalt pitch as well as 10 billion dollars in cash to establish the National Development Bank.

Seoul refused to accept Pyongyang's demand, leading to the failure of inter-Korean summit, the ex-president said.

In July 2010, a senior official of South Korea's National Intelligence Service (NIS) visited Pyongyang at the request of the DPRK's spy agency. The visit came some four months after a South Korean Navy corvette sank in waters off the disputed western sea border.

South Korea has insisted that it was caused by a DPRK torpedo attack, but Pyongyang has denied its involvement in the incident that killed 46 South Korean soldiers. In May, South Korea imposed the May 24 sanctions against the DPRK, which banned all inter- Korean cooperation except for the Kaesong Industrial Complex.

During the visit, the NIS official demanded that the DPRK apologize for the attack and take measures to prevent recurrence before inter-Korean summit is held, but the DPRK said it would express regrets over the incident as a brethren country for courtesy's sake while demanding 500,000 tons of rice for aid, the former president recalled.

In December 2010, two military officials from the DPRK visited Seoul to have behind-the-scene discussions about inter-Korean summit, just a month after the DPRK launched artillery attack on Yeonpyeong island in Yellow Sea. It claimed lives of two civilians and two marines.

In early 2011, the two Koreas had behind-the-scene contacts in New York, before secret meeting in Beijing in May 2011, but he and Kim Jong Il failed to sit down face-to-face for wide differences on the warship sinking incident.

In December 2011, Kim Jong Un took power on the death of his father Kim Jong Il.