North Korea said on Monday it would "never deal with" South Korean President Lee Myung-bak in a statement carried by Xinhua news agency.
North Korea's National Defense Commission said Lee and his government were undermining efforts to reunify the two nations.
Tensions have been high between the two Koreas in the wake of two deadly incidents last year.
South Korea has accused Pyongyang of sinking its Cheonan warship last March, with the loss of 46 lives. Four South Koreans were killed when North Korea shelled a border island in November.
Six-nation talks aimed at ending Pyongyang's nuclear program have also been stalled for months.
MOSCOW, May 30 (RIA Novosti)
