The International Criminal Court (ICC) is conducting a preliminary examination into North Korea’s artillery attack on South Korea’s Yeonpyeong Island in late November and the sinking of the South’s “Cheonan” naval vessel in March.

ICC Prosecutor Luis Moreno-Ocampo told a news conference at U.N. headquarters that his office opened a preliminary examination to determine whether the sinking of the Cheonan and the North’s shelling of Yeonpyeong constitute war crimes.

He added that the decision whether to launch a full-scale investigation into the incidents will be based on the preliminary probe.

Moreno-Ocampo noted that the preliminary examination was not launched at the request of any state but will be conducted based on appeals by South Korean students and citizens.

He said that South Korea has been a State Party to the Rome Statute of the International Criminal Court since 2002 and that there is an obvious need to investigate the details of the two incidents.