There are military options for South Korea beyond firing missiles, said John Delury, who studies North and South Korea at the Asia Society.

CNN: STORY HIGHLIGHTS

That tough stance, while worrying to some, is likely to be a kind of "pre-emptive rhetorical deterrence", according to analysts such as John Delury, a professor of International Studies at Seoul's Yonsei University.

BBC: Anxiety in South as N Korea rhetoric escalates

"I don't think this latest spike in the cycle of provocation and response undermines her whole platform of seeking to somehow re-engage the North, " said John Delury, an analyst at Seoul's Yonsei University.

NPR: SKorea's New Leader Faces NKorea Nuke Crisis