"China is expected [to act] by the rest of the world and whether they are able to give up the nuclear missile development of North Korea, if that cannot be done, the preemptive strike of the United States will be approved," Nakatani said at the Center for Strategic and International Studies.
Tensions on the Korean Peninsula escalated as North Korea carried out a number of missile launches and nuclear tests in the recent months, which are considered to be in violation of the UN Security Council resolutions.
As a response to the potential use of nuclear weapons, the United States sent a naval group led by US aircraft carrier Carl Vinson to the Korean Peninsula. US media reported that US President Donald Trump might order a strike against North Korea in light of its military activities.