South Korea's defense minister says the danger is growing that North Korea will launch a “surprise provocation” against the South.

At a parliamentary session Monday, Defense Minister Kim Kwan-jin pointed to a recent barrage of strongly-worded threats from Pyongyang.

Kim said the South's military is keeping a close watch on the North's forces and maintaining a readiness to cope with any type of provocation.

Relations have worsened since President Lee Myung-bak took office in February, 2008, and linked major aid to the North's nuclear disarmament.

Seoul has accused the North of sinking one of its warships in March of 2010 with the loss of 46 lives.

The North denies involvement in the sinking, but shelled a South Korean border island last November, killing four people.

Pyongyang refuses to apologize for either incident, a precondition set by Seoul before any serious talks can begin.