South Korea's defense chief nominee said Friday South Korea will respond with an air raid to the Democratic People's Republic of Korea (DPRK) in case of further aggression by the wartime enemy.

South Korea will "definitely" opt for air bombardment of the DPRK if it launches another attack on South Korea, Kim Kwan-jin, the 61-year-old former chairman of the Joint Chiefs of Staff (JCS), told lawmakers at his confirmation hearing.

But the next possible provocation by the DPRK can come in a " totally unexpected" way, with its behavior becoming increasingly difficult to predict and the threat getting bigger, the nominee added.

Kim's nomination came shortly after the DPRK shelled a South Korean western border island near a disputed sea border last Tuesday in what Seoul said was an "unprovoked attack," killing two marines and two civilians.

The DPRK claims the attack was provoked by South Korean and U.S. forces then engaged in massive joint naval drills and was for "self-defense."

The trade of fire was the latest in a series of perceived military bungles that put pressure on outgoing minister Kim Tae-young, who had already tendered his resignation following the fatal March sinking of a South Korean warship.

The minister-designate, when serving as the JCS chief in the previous administration, led Seoul's efforts to retake wartime operational control from Washington.

The transfer, originally slated for 2012, has been postponed till 2015 following the sinking.