A former South Korean president says that late North Korean leader Kim Jong Il repeatedly pushed for summit talks with him. But he says the plans failed because Pyongyang demanded $10 billion and large-scale shipments of food and fertilizer.

Key parts of the memoir by ex-President Lee Myung-bak were provided Thursday to reporters in advance ahead of its publication next week.

The memoir reveals that senior officials from the two Koreas made secret visits to the opposing countries in 2010, when two deadly attacks blamed on Pyongyang killed 50 South Koreans.

Lee says a Pyongyang envoy who came south was later publicly executed after returning to the North.

The Koreas have held two summit talks in 2000 and 2007 since their division 70 years ago.