SEOUL - The Republic of Korea (ROK) named Friday Lee Hee-won, a former presidential security aide, as new defense minister as the former defense chief resigned to shoulder responsibility for a series of recent mishaps, Seoul's presidential office Cheong Wa Dae said.

President Lee Myung-bak accepted defense minister Kim Tae-young' s resignation offer Thursday afternoon, months after Kim tendered his resignation following accusations that he mishandled the military's initial responses to the presumed March torpedo attack by the Democratic People's Republic of Korea (DPRK) on a ROK warship.

Lee delayed formerly accepting the resignation offer due to a series of pressing issues at hand, such as follow-up measures to cope with the ship sinking and an annual defense ministerial meeting with Washington, presidential chief of staff Yim Tae-hee said Thursday.

But recent mishaps in the military, including successive incidents and the DPRK's fatal shelling of a ROK island, have pushed the president to eventually accept Kim's offer to step down as a means to boost the military morale, Yim said.

The defense ministry came under fire for what some say was a belated response for the artillery attack, which prompted return fire from ROK. The clash left two ROK marines and two civilians killed, while damages to the DPRK have yet to be verified.

The DPRK claims ROK shells fell first into its side of the disputed sea border in the Yellow Sea, fixed by the US-led United Nations Command after the 1950-1953 Korean War. ROK was engaged in a massive annual maritime drill.

The outgoing minister will continue his work before his successor takes over after winning parliamentary approval. The Cheong Wa Dae reportedly held a mock hearing of Lee Hee-won late Thursday.