South Korea lambasted the extremist Islamic State (IS) group Monday for its killing of a Japanese hostage, saying that innocent civilians should not be the target of terrorism.

The militant IS group claimed Sunday that it had executed Haruna Yukawa, one of two Japanese hostages it had been holding.

The group is now demanding that Jordan release a female Iraqi terrorist in exchange for the other Japanese hostage, Kenjin Goto, a 47-year-old journalist.

The South Korean government said it cannot help feeling shock and anger in response to the innocent Japanese civilian's death.

"We have kept a firm stance that the sacrifice of innocent civilians through terrorist acts cannot be justified for any reason," South Korea's foreign ministry said in a statement.

"We share the pain and sorrow that the Japanese people are undergoing and hope that the remaining hostage will come back home safely." (Yonhap)