South Korean news outlets say North Korea is plotting to kill South Korea's defense minister because of his hardline stance against the communist regime.

The outlets quote government sources as saying South Korean intelligence has received reports that a team has been sent to assassinate Defense Minister Kim Kwan-jin. They say military and intelligence officials have not determined whether the would-be assassins are from North Korea, or foreign nationals who entered the South from a third country on Pyongyang's orders.

The defense minister has vowed that Seoul will respond with force if the North carries out any more military attacks against South Korea. Four people were killed when North Korea shelled a border island last December.

North Korea's state-run media has denounced Kim as a traitor.

North Korea has sent agents into the South to assassinate key South Korean officials and defectors in the past. A nephew of leader Kim Jong-Il, who had defected, was killed by the North's agents in Seoul in 1997.